The voting period for the Debian Project Leader election has ended. Please join us in congratulating Andreas Tille as the new Debian Project Leader. The new term for the project leader started on 2024-04-21. 369 of 1,010 Debian Developers voted using the Condorcet method. More information about the results of the voting are available on the Debian Project Leader Elections 2024 page. Many thanks all of our Developers for voting.

I have mailed to a Debian bug on allegro4.4 describing my reasoning regarding the allegro libraries in short, allegro4.4 is pretty much dead upstream, and my interest was basically to keep alex4 (which is cool) in Debian, but since it migrated to non-free, my interest in allegro4.4 has waned. So, if anybody would like to still see allegro4.4 in Debian, please step up now and help out. Since it is dead upstream, my reasoning is that it is better to remove it from Debian if no maintainer who wants to help steps up. Previously Tobias Hansen has helped out, but now it is 8 (!) years since his last upload of either package. (Please don t interpret this as judgement, I am very happy for the help he has provided and all the work he has done on the packages). Allegro5 is another deal still active upstream, and I have kept it up to date in Debian, and while I have held the latest upload a short while because of the time_t transition, it will come sooner or later There I am also waiting on a final decision on this bug from upstream. Other than that allegro 5 is in a very good state, and I will keep maintaining it as long as I can. But help would of course be appreciated on allegro5 too.

The Debian Project Developers will shortly vote for a new Debian Project Leader known as the DPL. The DPL is the official representative of representative of The Debian Project tasked with managing the overall project, its vision, direction, and finances. The DPL is also responsible for the selection of Delegates, defining areas of responsibility within the project, the coordination of Developers, and making decisions required for the project. Our outgoing and present DPL Jonathan Carter served 4 terms, from 2020 through 2024. Jonathan shared his last Bits from the DPL post to Debian recently and his hopes for the future of Debian. Recently, we sat with the two present candidates for the DPL position asking questions to find out who they really are in a series of interviews about their platforms, visions for Debian, lives, and even their favorite text editors. The interviews were conducted by disaster2life (Yashraj Moghe) and made available from video and audio transcriptions:

• Andreas Tille [Interview]
• Sruthi Chandran [this document]

Voting for the position starts on April 6, 2024. Editors' note: This is our official return to Debian interviews, readers should stay tuned for more upcoming interviews with Developers and other important figures in Debian as part of our "Meet your Debian Developer" series. We used the following tools and services: Turboscribe.ai for the transcription from the audio and video files, IRC: Oftc.net for communication, Jitsi meet for interviews, and Open Broadcaster Software (OBS) for editing and video. While we encountered many technical difficulties in the return to this process, we are still able and proud to present the transcripts of the interviews edited only in a few areas for readability. 2024 Debian Project Leader Candidate: Sruthi Chandran Sruthi's interview Hi Sruthi, so for the first question, who are you and could you tell us a little bit about yourself? [Sruthi]:

I usually talk about me whenever I am talking about answering the question who am I, I usually say like I am a librarian turned free software enthusiast and a Debian Developer. So I had no technical background and I learned, I was introduced to free software through my husband and then I learned Debian packaging, and eventually I became a Debian Developer. So I always give my example to people who say I am not technically inclined, I don't have technical background so I can't contribute to free software. So yeah, that's what I refer to myself.

For the next question, could you tell me what do you do in Debian, and could you mention your story up until here today? [Sruthi]:

Okay, so let me start from my initial days in Debian. I started contributing to Debian, my first contribution was a Tibetan font. We went to a Tibetan place and they were saying they didn't have a font in Linux. So that's how I started contributing. Then I moved on to Ruby packages, then I have some JavaScript and Go packages, all dependencies of GitLab. So I was involved with maintaining GitLab for some time, now I'm not very active there. But yeah, so GitLab was the main package I was contributing to since I contributed since 2016 to maybe like 2020 or something. Later I have come [over to] packaging. Now I am part of some of the teams, delegated teams, like community team and outreach team, as well as the Debconf committee. And the biggest, I think, my activity in Debian, I would say is organizing Debconf 2023. So it was a great experience and yeah, so that's my story in Debian.

So what are three key terms about you and your candidacy? [Sruthi]:

Okay, let me first think about it. For candidacy, I can start with diversity is one point I started expressing from the first time I contested for DPL. But to be honest, that's the main point I want to bring.

[Yashraj]:

So for diversity, if you could break down your thoughts on diversity and make them, [about] your three points including diversity.

[Sruthi]:

So in addition to, eventually when starting it was just diversity. Now I have like a bit more ideas, like community, like I want to be a leader for the Debian community. More than, I don't know, maybe people may not agree, but I would say I want to be a leader of Debian community rather than a Debian operating system. I connect to community more and third point I would say.

The term of a DPL lasts for an year. So what do you think during, what would you try to do during that, that you can't do from your position now? [Sruthi]:

Okay. So I, like, I am very happy with the structure of Debian and how things work in Debian. Like you can do almost a lot of things, like almost all things without being a DPL. Whatever change you want to bring about or whatever you want to do, you can do without being a DPL. Anyone, like every DD has the same rights. Only things I feel [the] DPL has hold on are mainly the budget or the funding part, which like, that's where they do the decision making part. And then comes like, and one advantage of DPL driving some idea is that somehow people tend to listen to that with more, like, tend to give more attention to what DPL is saying rather than a normal DD. So I wanted to, like, I have answered some of the questions on how to, how I plan to do the financial budgeting part, how I want to handle, like, and the other thing is using the extra attention that I get as a DPL, I would like to obviously start with the diversity aspect in Debian. And yeah, like, I, what I want to do is not, like, be a leader and say, like, take Debian to one direction where I want to go, but I would rather take suggestions and inputs from the whole community and go about with that. So yes, that's what I would say.

And taking a less serious question now, what is your preferred text editor? [Sruthi]:

Vim.

[Yashraj]:

Vim, wholeheartedly team Vim?

[Sruthi]:

Yes.

[Yashraj]:

Great. Well, this was made in Vim, all the text for this.

[Sruthi]:

So, like, since you mentioned extra data, I'll give my example, like, it's just a fun note, when I started contributing to Debian, as I mentioned, I didn't have any knowledge about free software, like Debian, and I was not used to even using Linux. So, and I didn't have experience with these text editors. So, when I started contributing, I used to do the editing part using gedit. So, that's how I started. Eventually, I moved to Nano, and once I reached Vim, I didn't move on.

Team Vim. Next question. What, what do you think is the importance of the Debian project in the world today? And where would you like to see it in 10 years, like 10 years into the future? [Sruthi]:

Okay. So, Debian, as we all know, is referred to as the universal operating system without, like, it is said for a reason. We have hundreds and hundreds of operating systems, like Linux, distributions based on Debian. So, I believe Debian, like even now, Debian has good influence on the, at least on the Linux or Linux ecosystem. So, what we implement in Debian has, like, is going to affect quite a lot of, like, a very good percentage of people using Linux. So, yes. So, I think Debian is one of the leading Linux distributions. And I think in 10 years, we should be able to reach a position, like, where we are not, like, even now, like, even these many years after having Linux, we face a lot of problems in newer and newer hardware coming up and installing on them is a big problem. Like, firmwares and all those things are getting more and more complicated. Like, it should be getting simpler, but it's getting more and more complicated. So, I, one thing I would imagine, like, I don't know if we will ever reach there, but I would imagine that eventually with the Debian, we should be able to have some, at least a few of the hardware developers or hardware producers have Debian pre-installed and those kind of things. Like, not, like, become, I'm not saying it's all, it's also available right now. What I'm saying is that it becomes prominent enough to be opted as, like, default distro.

What part of Debian has made you And what part of the project has kept you going all through these years? [Sruthi]:

Okay. So, I started to contribute in 2016, and I was part of the team doing GitLab packaging, and we did have a lot of training workshops and those kind of things within India. And I was, like, I had interacted with some of the Indian DDs, but I never got, like, even through chat or mail. I didn't have a lot of interaction with the rest of the world, DDs. And the 2019 Debconf changed my whole perspective about Debian. Before that, I wasn't, like, even, I was interested in free software. I was doing the technical stuff and all. But after DebConf, my whole idea has been, like, my focus changed to the community. Debian community is a very welcoming, very interesting community to be with. And so, I believe that, like, 2019 DebConf was a for me. And that kept, from 2019, my focus has been to how to support, like, how, I moved to the community part of Debian from there. Then in 2020 I became part of the community team, and, like, I started being part of other teams. So, these, I would say, the Debian community is the one, like, aspect of Debian that keeps me whole, keeps me held on to the Debian ecosystem as a whole.

Continuing to speak about Debian, what do you think, what is the first thing that comes to your mind when you think of Debian, like, the word, the community, what's the first thing? [Sruthi]:

I think I may sound like a broken record or something.

[Yashraj]:

No, no.

[Sruthi]:

Again, I would say the Debian community, like, it's the people who makes Debian, that makes Debian special. Like, apart from that, if I say, I would say I'm very, like, one part of Debian that makes me very happy is the, how the governing system of Debian works, the Debian constitution and all those things, like, it's a very unique thing for Debian. And, and it's like, when people say you can't work without a proper, like, establishment or even somebody deciding everything for you, it's difficult. When people say, like, we have been, Debian has been proving it for quite a long time now, that it's possible. So, so that's one thing I believe, like, that's one unique point. And I am very proud about that.

What areas do you think Debian is failing in, how can it (that standing) be improved? [Sruthi]:

So, I think where Debian is failing now is getting new people into Debian. Like, I don't remember, like, exactly the answer. But I remember hearing someone mention, like, the average age of a Debian Developer is, like, above 40 or 45 or something, like, exact age, I don't remember. But it's like, Debian is getting old. Like, the people in Debian are getting old and we are not getting enough of new people into Debian. And that's very important to have people, like, new people coming up. Otherwise, eventually, like, after a few years, nobody, like, we won't have enough people to take the project forward. So, yeah, I believe that is where we need to work on. We are doing some efforts, like, being part of GSOC or outreachy and having maybe other events, like, local events. Like, we used to have a lot of Debian packaging workshops in India. And those kind of, I think, in Brazil and all, they all have, like, local communities are doing. But we are not very successful in retaining the people who maybe come and try out things. But we are not very good at retaining the people, like, retaining people who come. So, we need to work on those things. Right now, I don't have a solid answer for that. But one thing, like, I was thinking about is, like, having a Debian specific outreach project, wherein the focus will be about the Debian, like, starting will be more on, like, usually what happens in GSOC and outreach is that people come, have the, do the contributions, and they go back. Like, they don't have that connection with the Debian, like, Debian community or Debian project. So, what I envision with these, the Debian outreach, the Debian specific outreach is that we have some part of the internship, like, even before starting the internship, we have some sessions and, like, with the people in Debian having, like, getting them introduced to the Debian philosophy and Debian community and Debian, how Debian works. And those things, we focus on that. And then we move on to the technical internship parts. So, I believe this could do some good in having, like, when you have people you can connect to, you tend to stay back in a project mode. When you feel something more than, like, right now, we have so many technical stuff to do, like, the choice for a college student is endless. So, if they want, if they stay back for something, like, maybe for Debian, I would say, we need to have them connected to the Debian project before we go into technical parts. Like, technical parts, like, there are other things as well, where they can go and do the technical part, but, like, they can come here, like, yeah. So, that's what I was saying. Focused outreach projects is one thing. That's just one. That's not enough. We need more of, like, more ideas to have more new people come up. And I'm very happy with, like, the DebConf thing. We tend to get more and more people from the places where we have a DebConf. Brazil is an example. After the Debconf, they have quite a good improvement on Debian contributors. And I think in India also, it did give a good result. Like, we have more people contributing and staying back and those things. So, yeah. So, these were the things I would say, like, we can do to improve.

For the final question, what field in free software do you, what field in free software generally do you think requires the most work to be put into it? What do you think is Debian's part in that field? [Sruthi]:

Okay. Like, right now, what comes to my mind is the free software licenses parts. Like, we have a lot of free software licenses, and there are non-free software licenses. But currently, I feel free software is having a big problem in enforcing these licenses. Like, there are, there may be big corporations or like some people who take up the whole, the code and may not follow the whole, for example, the GPL licenses. Like, we don't know how much of those, how much of the free softwares are used in the bigger things. Yeah, I agree. There are a lot of corporations who are afraid to touch free software. But there would be good amount of free software, free work that converts into property, things violating the free software licenses and those things. And we do not have the kind of like, we have SFLC, SFC, etc. But still, we do not have the ability to go behind and trace and implement the licenses. So, enforce those licenses and bring people who are violating the licenses forward and those kind of things is challenging because one thing is it takes time, like, and most importantly, money is required for the legal stuff. And not always people who like people who make small software, or maybe big, but they may not have the kind of time and money to have these things enforced. So, that's a big challenge free software is facing, especially in our current scenario. I feel we are having those, like, we need to find ways how we can get it sorted. I don't have an answer right now what to do. But this is a challenge I felt like and Debian's part in that. Yeah, as I said, I don't have a solution for that. But the Debian, so DFSG and Debian sticking on to the free software licenses is a good support, I think.

So, that was the final question, Do you have anything else you want to mention for anyone watching this? [Sruthi]:

Not really, like, I am happy, like, I think I was able to answer the questions. And yeah, I would say who is watching. I won't say like, I'm the best DPL candidate, you can't have a better one or something. I stand for a reason. And if you believe in that, or the Debian community and Debian diversity, and those kinds of things, if you believe it, I hope you would be interested, like, you would want to vote for me. That's it. Like, I'm not, I'll make it very clear. I'm not doing a technical leadership part here. So, those, I can't convince people who want technical leadership to vote for me. But I would say people who connect with me, I hope they vote for me.

The Debian Project Developers will shortly vote for a new Debian Project Leader known as the DPL. The Project Leader is the official representative of The Debian Project tasked with managing the overall project, its vision, direction, and finances. The DPL is also responsible for the selection of Delegates, defining areas of responsibility within the project, the coordination of Developers, and making decisions required for the project. Our outgoing and present DPL Jonathan Carter served 4 terms, from 2020 through 2024. Jonathan shared his last Bits from the DPL post to Debian recently and his hopes for the future of Debian. Recently, we sat with the two present candidates for the DPL position asking questions to find out who they really are in a series of interviews about their platforms, visions for Debian, lives, and even their favorite text editors. The interviews were conducted by disaster2life (Yashraj Moghe) and made available from video and audio transcriptions:

• Andreas Tille [this document]
• Sruthi Chandran [Interview]

Voting for the position starts on April 6, 2024. Editors' note: This is our official return to Debian interviews, readers should stay tuned for more upcoming interviews with Developers and other important figures in Debian as part of our "Meet your Debian Developer" series. We used the following tools and services: Turboscribe.ai for the transcription from the audio and video files, IRC: Oftc.net for communication, Jitsi meet for interviews, and Open Broadcaster Software (OBS) for editing and video. While we encountered many technical difficulties in the return to this process, we are still able and proud to present the transcripts of the interviews edited only in a few areas for readability. 2024 Debian Project Leader Candidate: Andrea Tille Andreas' Interview Who are you? Tell us a little about yourself. [Andreas]:

How am I? Well, I'm, as I wrote in my platform, I'm a proud grandfather doing a lot of free software stuff, doing a lot of sports, have some goals in mind which I like to do and hopefully for the best of Debian.

And How are you today? [Andreas]:

How I'm doing today? Well, actually I have some headaches but it's fine for the interview. So, usually I feel very good. Spring was coming here and today it's raining and I plan to do a bicycle tour tomorrow and hope that I do not get really sick but yeah, for the interview it's fine.

What do you do in Debian? Could you mention your story here? [Andreas]:

Yeah, well, I started with Debian kind of an accident because I wanted to have some package salvaged which is called WordNet. It's a monolingual dictionary and I did not really plan to do more than maybe 10 packages or so. I had some kind of training with xTeddy which is totally unimportant, a cute teddy you can put on your desktop. So, and then well, more or less I thought how can I make Debian attractive for my employer which is a medical institute and so on. It could make sense to package bioinformatics and medicine software and it somehow evolved in a direction I did neither expect it nor wanted to do, that I'm currently the most busy uploader in Debian, created several teams around it. DebianMate is very well known from me. I created the Blends team to create teams and techniques around what we are doing which was Debian TIS, Debian Edu, Debian Science and so on and I also created the packaging team for R, for the statistics package R which is technically based and not topic based. All these blends are covering a certain topic and R is just needed by lots of these blends. So, yeah, and to cope with all this I have written a script which is routing an update to manage all these uploads more or less automatically. So, I think I had one day where I uploaded 21 new packages but it's just automatically generated, right? So, it's on one day more than I ever planned to do.

What is the first thing you think of when you think of Debian? Editors' note: The question was misunderstood as the worst thing you think of when you think of Debian [Andreas]:

The worst thing I think about Debian, it's complicated. I think today on Debian board I was asked about the technical progress I want to make and in my opinion we need to standardize things inside Debian. For instance, bringing all the packages to salsa, follow some common standards, some common workflow which is extremely helpful. As I said, if I'm that productive with my own packages we can adopt this in general, at least in most cases I think. I made a lot of good experience by the support of well-formed teams. Well-formed teams are those teams where people support each other, help each other. For instance, how to say, I'm a physicist by profession so I'm not an IT expert. I can tell apart what works and what not but I'm not an expert in those packages. I do and the amount of packages is so high that I do not even understand all the techniques they are covering like Go, Rust and something like this. And I also don't speak Java and I had a problem once in the middle of the night and I've sent the email to the list and was a Java problem and I woke up in the morning and it was solved. This is what I call a team. I don't call a team some common repository that is used by random people for different packages also but it's working together, don't hesitate to solve other people's problems and permit people to get active. This is what I call a team and this is also something I observed in, it's hard to give a percentage, in a lot of other teams but we have other people who do not even understand the concept of the team. Why is working together make some advantage and this is also a tough thing. I [would] like to tackle in my term if I get elected to form solid teams using the common workflow. This is one thing. The other thing is that we have a lot of good people in our infrastructure like FTP masters, DSA and so on. I have the feeling they have a lot of work and are working more or less on their limits, and I like to talk to them [to ask] what kind of change we could do to move that limits or move their personal health to the better side.

The DPL term lasts for a year, What would you do during that you couldn't do now? [Andreas]:

Yeah, well this is basically what I said are my main issues. I need to admit I have no really clear imagination what kind of tasks will come to me as a DPL because all these financial issues and law issues possible and issues [that] people who are not really friendly to Debian might create. I'm afraid these things might occupy a lot of time and I can't say much about this because I simply don't know.

What are three key terms about you and your candidacy? [Andreas]:

As I said, I like to work on standards, I d like to make Debian try [to get it right so] that people don't get overworked, this third key point is be inviting to newcomers, to everybody who wants to come. Yeah, I also mentioned in my term this diversity issue, geographical and from gender point of view. This may be the three points I consider most important.

Preferred text editor? [Andreas]:

Yeah, my preferred one? Ah, well, I have no preferred text editor. I'm using the Midnight Commander very frequently which has an internal editor which is convenient for small text. For other things, I usually use VI but I also use Emacs from time to time. So, no, I have not preferred text editor. Whatever works nicely for me.

What is the importance of the community in the Debian Project? How would like to see it evolving over the next few years? [Andreas]:

Yeah, I think the community is extremely important. So, I was on a lot of DebConfs. I think it's not really 20 but 17 or 18 DebCons and I really enjoyed these events every year because I met so many friends and met so many interesting people that it's really enriching my life and those who I never met in person but have read interesting things and yeah, Debian community makes really a part of my life.

And how do you think it should evolve specifically? [Andreas]:

Yeah, for instance, last year in Kochi, it became even clearer to me that the geographical diversity is a really strong point. Just discussing with some women from India who is afraid about not coming next year to Busan because there's a problem with Shanghai and so on. I'm not really sure how we can solve this but I think this is a problem at least I wish to tackle and yeah, this is an interesting point, the geographical diversity and I'm running the so-called mentoring of the month. This is a small project to attract newcomers for the Debian Med team which has the focus on medical packages and I learned that we had always men applying for this and so I said, okay, I dropped the constraint of medical packages. Any topic is fine, I teach you packaging but it must be someone who does not consider himself a man. I got only two applicants, no, actually, I got one applicant and one response which was kind of strange if I'm hunting for women or so. I did not understand but I got one response and interestingly, it was for me one of the least expected counters. It was from Iran and I met a very nice woman, very open, very skilled and gifted and did a good job or have even lose contact today and maybe we need more actively approach groups that are underrepresented. I don't know if what's a good means which I did but at least I tried and so I try to think about these kind of things.

What part of Debian has made you smile? What part of the project has kept you going all through the years? [Andreas]:

Well, the card game which is called Mao on the DebConf made me smile all the time. I admit I joined only two or three times even if I really love this kind of games but I was occupied by other stuff so this made me really smile. I also think the first online DebConf in 2020 made me smile because we had this kind of short video sequences and I tried to make a funny video sequence about every DebConf I attended before. This is really funny moments but yeah, it's not only smile but yeah. One thing maybe it's totally unconnected to Debian but I learned personally something in Debian that we have a do-ocracy and you can do things which you think that are right if not going in between someone else, right? So respect everybody else but otherwise you can do so. And in 2020 I also started to take trees which are growing widely in my garden and plant them into the woods because in our woods a lot of trees are dying and so I just do something because I can. I have the resource to do something, take the small tree and bring it into the woods because it does not harm anybody. I asked the forester if it is okay, yes, yes, okay. So everybody can do so but I think the idea to do something like this came also because of the free software idea. You have the resources, you have the computer, you can do something and you do something productive, right? And when thinking about this I think it was also my Debian work. Meanwhile I have planted more than 3,000 trees so it's not a small number but yeah, I enjoy this.

What part of Debian would you have some criticisms for? [Andreas]:

Yeah, it's basically the same as I said before. We need more standards to work together. I do not want to repeat this but this is what I think, yeah.

What field in Free Software generally do you think requires the most work to be put into it? What do you think is Debian's part in the field? [Andreas]:

It's also in general, the thing is the fact that I'm maintaining packages which are usually as modern software is maintained in Git, which is fine but we have some software which is at Sourceport, we have software laying around somewhere, we have software where Debian somehow became Upstream because nobody is caring anymore and free software is very different in several things, ways and well, I in principle like freedom of choice which is the basic of all our work. Sometimes this freedom goes in the way of productivity because everybody is free to re-implement. You asked me for the most favorite editor. In principle one really good working editor would be great to have and would work and we have maybe 500 in Debian or so, I don't know. I could imagine if people would concentrate and say five instead of 500 editors, we could get more productive, right? But I know this will not happen, right? But I think this is one thing which goes in the way of making things smooth and productive and we could have more manpower to replace one person who's [having] children, doing some other stuff and can't continue working on something and maybe this is a problem I will not solve, definitely not, but which I see.

What do you think is Debian's part in the field? [Andreas]:

Yeah, well, okay, we can bring together different Upstreams, so we are building some packages and have some general overview about similar things and can say, oh, you are doing this and some other person is doing more or less the same, do you want to join each other or so, but this is kind of a channel we have to our Upstreams which is probably not very successful. It starts with code copies of some libraries which are changed a little bit, which is fine license-wise, but not so helpful for different things and so I've tried to convince those Upstreams to forward their patches to the original one, but for this and I think we could do some kind of, yeah, [find] someone who brings Upstream together or to make them stop their forking stuff, but it costs a lot of energy and we probably don't have this and it's also not realistic that we can really help with this problem.

Do you have any questions for me? [Andreas]:

I enjoyed the interview, I enjoyed seeing you again after half a year or so. Yeah, actually I've seen you in the eating room or cheese and wine party or so, I do not remember we had to really talk together, but yeah, people around, yeah, for sure. Yeah.

Dear Debianites This morning I decided to just start writing Bits from DPL and send whatever I have by 18:00 local time. Here it is, barely proof read, along with all it's warts and grammar mistakes! It's slightly long and doesn't contain any critical information, so if you're not in the mood, don't feel compelled to read it! Get ready for a new DPL! Soon, the voting period will start to elect our next DPL, and my time as DPL will come to an end. Reading the questions posted to the new candidates on debian-vote, it takes quite a bit of restraint to not answer all of them myself, I think I can see how that aspect contributed to me being reeled in to running for DPL! In total I've done so 5 times (the first time I ran, Sam was elected!). Good luck to both Andreas and Sruthi, our current DPL candidates! I've already started working on preparing handover, and there's multiple request from teams that have came in recently that will have to wait for the new term, so I hope they're both ready to hit the ground running! Things that I wish could have gone better Communication Recently, I saw a t-shirt that read:

Adulthood is saying, 'But after this week things will slow down a bit' over and over until you die.

I can relate! With every task, crisis or deadline that appears, I think that once this is over, I'll have some more breathing space to get back to non-urgent, but important tasks. "Bits from the DPL" was something I really wanted to get right this last term, and clearly failed spectacularly. I have two long Bits from the DPL drafts that I never finished, I tend to have prioritised problems of the day over communication. With all the hindsight I have, I'm not sure which is better to prioritise, I do rate communication and transparency very highly and this is really the top thing that I wish I could've done better over the last four years. On that note, thanks to people who provided me with some kind words when I've mentioned this to them before. They pointed out that there are many other ways to communicate and be in touch with the community, and they mentioned that they thought that I did a good job with that. Since I'm still on communication, I think we can all learn to be more effective at it, since it's really so important for the project. Every time I publicly spoke about us spending more money, we got more donations. People out there really like to see how we invest funds in to Debian, instead of just making it heap up. DSA just spent a nice chunk on money on hardware, but we don't have very good visibility on it. It's one thing having it on a public line item in SPI's reporting, but it would be much more exciting if DSA could provide a write-up on all the cool hardware they're buying and what impact it would have on developers, and post it somewhere prominent like debian-devel-announce, Planet Debian or Bits from Debian (from the publicity team). I don't want to single out DSA there, it's difficult and affects many other teams. The Salsa CI team also spent a lot of resources (time and money wise) to extend testing on AMD GPUs and other AMD hardware. It's fantastic and interesting work, and really more people within the project and in the outside world should know about it! I'm not going to push my agendas to the next DPL, but I hope that they continue to encourage people to write about their work, and hopefully at some point we'll build enough excitement in doing so that it becomes a more normal part of our daily work. Founding Debian as a standalone entity This was my number one goal for the project this last term, which was a carried over item from my previous terms. I'm tempted to write everything out here, including the problem statement and our current predicaments, what kind of ground work needs to happen, likely constitutional changes that need to happen, and the nature of the GR that would be needed to make such a thing happen, but if I start with that, I might not finish this mail. In short, I 100% believe that this is still a very high ranking issue for Debian, and perhaps after my term I'd be in a better position to spend more time on this (hmm, is this an instance of "The grass is always better on the other side", or "Next week will go better until I die?"). Anyway, I'm willing to work with any future DPL on this, and perhaps it can in itself be a delegation tasked to properly explore all the options, and write up a report for the project that can lead to a GR. Overall, I'd rather have us take another few years and do this properly, rather than rush into something that is again difficult to change afterwards. So while I very much wish this could've been achieved in the last term, I can't say that I have any regrets here either. My terms in a nutshell COVID-19 and Debian 11 era My first term in 2020 started just as the COVID-19 pandemic became known to spread globally. It was a tough year for everyone, and Debian wasn't immune against its effects either. Many of our contributors got sick, some have lost loved ones (my father passed away in March 2020 just after I became DPL), some have lost their jobs (or other earners in their household have) and the effects of social distancing took a mental and even physical health toll on many. In Debian, we tend to do really well when we get together in person to solve problems, and when DebConf20 got cancelled in person, we understood that that was necessary, but it was still more bad news in a year we had too much of it already. I can't remember if there was ever any kind of formal choice or discussion about this at any time, but the DebConf video team just kind of organically and spontaneously became the orga team for an online DebConf, and that lead to our first ever completely online DebConf. This was great on so many levels. We got to see each other's faces again, even though it was on screen. We had some teams talk to each other face to face for the first time in years, even though it was just on a Jitsi call. It had a lasting cultural change in Debian, some teams still have video meetings now, where they didn't do that before, and I think it's a good supplement to our other methods of communication. We also had a few online Mini-DebConfs that was fun, but DebConf21 was also online, and by then we all developed an online conference fatigue, and while it was another good online event overall, it did start to feel a bit like a zombieconf and after that, we had some really nice events from the Brazillians, but no big global online community events again. In my opinion online MiniDebConfs can be a great way to develop our community and we should spend some further energy into this, but hey! This isn't a platform so let me back out of talking about the future as I see it... Despite all the adversity that we faced together, the Debian 11 release ended up being quite good. It happened about a month or so later than what we ideally would've liked, but it was a solid release nonetheless. It turns out that for quite a few people, staying inside for a few months to focus on Debian bugs was quite productive, and Debian 11 ended up being a very polished release. During this time period we also had to deal with a previous Debian Developer that was expelled for his poor behaviour in Debian, who continued to harass members of the Debian project and in other free software communities after his expulsion. This ended up being quite a lot of work since we had to take legal action to protect our community, and eventually also get the police involved. I'm not going to give him the satisfaction by spending too much time talking about him, but you can read our official statement regarding Daniel Pocock here: https://www.debian.org/News/2021/20211117 In late 2021 and early 2022 we also discussed our general resolution process, and had two consequent votes to address some issues that have affected past votes:

• https://www.debian.org/vote/2021/vote_003
• https://www.debian.org/vote/2022/vote_001

In my first term I addressed our delegations that were a bit behind, by the end of my last term all delegation requests are up to date. There's still some work to do, but I'm feeling good that I get to hand this over to the next DPL in a very decent state. Delegation updates can be very deceiving, sometimes a delegation is completely re-written and it was just 1 or 2 hours of work. Other times, a delegation updated can contain one line that has changed or a change in one team member that was the result of days worth of discussion and hashing out differences. I also received quite a few requests either to host a service, or to pay a third-party directly for hosting. This was quite an admin nightmare, it either meant we had to manually do monthly reimbursements to someone, or have our TOs create accounts/agreements at the multiple providers that people use. So, after talking to a few people about this, we founded the DebianNet team (we could've admittedly chosen a better name, but that can happen later on) for providing hosting at two different hosting providers that we have agreement with so that people who host things under debian.net have an easy way to host it, and then at the same time Debian also has more control if a site maintainer goes MIA. More info: https://wiki.debian.org/Teams/DebianNet You might notice some Openstack mentioned there, we had some intention to set up a Debian cloud for hosting these things, that could also be used for other additional Debiany things like archive rebuilds, but these have so far fallen through. We still consider it a good idea and hopefully it will work out some other time (if you're a large company who can sponsor few racks and servers, please get in touch!) DebConf22 and Debian 12 era DebConf22 was the first time we returned to an in-person DebConf. It was a bit smaller than our usual DebConf - understandably so, considering that there were still COVID risks and people who were at high risk or who had family with high risk factors did the sensible thing and stayed home. After watching many MiniDebConfs online, I also attended my first ever MiniDebConf in Hamburg. It still feels odd typing that, it feels like I should've been at one before, but my location makes attending them difficult (on a side-note, a few of us are working on bootstrapping a South African Debian community and hopefully we can pull off MiniDebConf in South Africa later this year). While I was at the MiniDebConf, I gave a talk where I covered the evolution of firmware, from the simple e-proms that you'd find in old printers to the complicated firmware in modern GPUs that basically contain complete operating systems- complete with drivers for the device their running on. I also showed my shiny new laptop, and explained that it's impossible to install that laptop without non-free firmware (you'd get a black display on d-i or Debian live). Also that you couldn't even use an accessibility mode with audio since even that depends on non-free firmware these days. Steve, from the image building team, has said for a while that we need to do a GR to vote for this, and after more discussion at DebConf, I kept nudging him to propose the GR, and we ended up voting in favour of it. I do believe that someone out there should be campaigning for more free firmware (unfortunately in Debian we just don't have the resources for this), but, I'm glad that we have the firmware included. In the end, the choice comes down to whether we still want Debian to be installable on mainstream bare-metal hardware. At this point, I'd like to give a special thanks to the ftpmasters, image building team and the installer team who worked really hard to get the changes done that were needed in order to make this happen for Debian 12, and for being really proactive for remaining niggles that was solved by the time Debian 12.1 was released. The included firmware contributed to Debian 12 being a huge success, but it wasn't the only factor. I had a list of personal peeves, and as the hard freeze hit, I lost hope that these would be fixed and made peace with the fact that Debian 12 would release with those bugs. I'm glad that lots of people proved me wrong and also proved that it's never to late to fix bugs, everything on my list got eliminated by the time final freeze hit, which was great! We usually aim to have a release ready about 2 years after the previous release, sometimes there are complications during a freeze and it can take a bit longer. But due to the excellent co-ordination of the release team and heavy lifting from many DDs, the Debian 12 release happened 21 months and 3 weeks after the Debian 11 release. I hope the work from the release team continues to pay off so that we can achieve their goals of having shorter and less painful freezes in the future! Even though many things were going well, the ongoing usr-merge effort highlighted some social problems within our processes. I started typing out the whole history of usrmerge here, but it's going to be too long for the purpose of this mail. Important questions that did come out of this is, should core Debian packages be team maintained? And also about how far the CTTE should really be able to override a maintainer. We had lots of discussion about this at DebConf22, but didn't make much concrete progress. I think that at some point we'll probably have a GR about package maintenance. Also, thank you to Guillem who very patiently explained a few things to me (after probably having have to done so many times to others before already) and to Helmut who have done the same during the MiniDebConf in Hamburg. I think all the technical and social issues here are fixable, it will just take some time and patience and I have lots of confidence in everyone involved. UsrMerge wiki page: https://wiki.debian.org/UsrMerge DebConf 23 and Debian 13 era DebConf23 took place in Kochi, India. At the end of my Bits from the DPL talk there, someone asked me what the most difficult thing I had to do was during my terms as DPL. I answered that nothing particular stood out, and even the most difficult tasks ended up being rewarding to work on. Little did I know that my most difficult period of being DPL was just about to follow. During the day trip, one of our contributors, Abraham Raji, passed away in a tragic accident. There's really not anything anyone could've done to predict or stop it, but it was devastating to many of us, especially the people closest to him. Quite a number of DebConf attendees went to his funeral, wearing the DebConf t-shirts he designed as a tribute. It still haunts me when I saw his mother scream "He was my everything! He was my everything!", this was by a large margin the hardest day I've ever had in Debian, and I really wasn't ok for even a few weeks after that and I think the hurt will be with many of us for some time to come. So, a plea again to everyone, please take care of yourself! There's probably more people that love you than you realise. A special thanks to the DebConf23 team, who did a really good job despite all the uphills they faced (and there were many!). As DPL, I think that planning for a DebConf is near to impossible, all you can do is show up and just jump into things. I planned to work with Enrico to finish up something that will hopefully save future DPLs some time, and that is a web-based DD certificate creator instead of having the DPL do so manually using LaTeX. It already mostly works, you can see the work so far by visiting https://nm.debian.org/person/ACCOUNTNAME/certificate/ and replacing ACCOUNTNAME with your Debian account name, and if you're a DD, you should see your certificate. It still needs a few minor changes and a DPL signature, but at this point I think that will be finished up when the new DPL start. Thanks to Enrico for working on this! Since my first term, I've been trying to find ways to improve all our accounting/finance issues. Tracking what we spend on things, and getting an annual overview is hard, especially over 3 trusted organisations. The reimbursement process can also be really tedious, especially when you have to provide files in a certain order and combine them into a PDF. So, at DebConf22 we had a meeting along with the treasurer team and Stefano Rivera who said that it might be possible for him to work on a new system as part of his Freexian work. It worked out, and Freexian funded the development of the system since then, and after DebConf23 we handled the reimbursements for the conference via the new reimbursements site: https://reimbursements.debian.net/ It's still early days, but over time it should be linked to all our TOs and we'll use the same category codes across the board. So, overall, our reimbursement process becomes a lot simpler, and also we'll be able to get information like how much money we've spent on any category in any period. It will also help us to track how much money we have available or how much we spend on recurring costs. Right now that needs manual polling from our TOs. So I'm really glad that this is a big long-standing problem in the project that is being fixed. For Debian 13, we're waving goodbye to the KFreeBSD and mipsel ports. But we're also gaining riscv64 and loongarch64 as release architectures! I have 3 different RISC-V based machines on my desk here that I haven't had much time to work with yet, you can expect some blog posts about them soon after my DPL term ends! As Debian is a unix-like system, we're affected by the Year 2038 problem, where systems that uses 32 bit time in seconds since 1970 run out of available time and will wrap back to 1970 or have other undefined behaviour. A detailed wiki page explains how this works in Debian, and currently we're going through a rather large transition to make this possible. I believe this is the right time for Debian to be addressing this, we're still a bit more than a year away for the Debian 13 release, and this provides enough time to test the implementation before 2038 rolls along. Of course, big complicated transitions with dependency loops that causes chaos for everyone would still be too easy, so this past weekend (which is a holiday period in most of the west due to Easter weekend) has been filled with dealing with an upstream bug in xz-utils, where a backdoor was placed in this key piece of software. An Ars Technica covers it quite well, so I won't go into all the details here. I mention it because I want to give yet another special thanks to everyone involved in dealing with this on the Debian side. Everyone involved, from the ftpmasters to security team and others involved were super calm and professional and made quick, high quality decisions. This also lead to the archive being frozen on Saturday, this is the first time I've seen this happen since I've been a DD, but I'm sure next week will go better! Looking forward It's really been an honour for me to serve as DPL. It might well be my biggest achievement in my life. Previous DPLs range from prominent software engineers to game developers, or people who have done things like complete Iron Man, run other huge open source projects and are part of big consortiums. Ian Jackson even authored dpkg and is now working on the very interesting tag2upload service! I'm a relative nobody, just someone who grew up as a poor kid in South Africa, who just really cares about Debian a lot. And, above all, I'm really thankful that I didn't do anything major to screw up Debian for good. Not unlike learning how to use Debian, and also becoming a Debian Developer, I've learned a lot from this and it's been a really valuable growth experience for me. I know I can't possible give all the thanks to everyone who deserves it, so here's a big big thanks to everyone who have worked so hard and who have put in many, many hours to making Debian better, I consider you all heroes! -Jonathan

Photo by Pixabay

Ubuntu systems typically have up to 3 kernels installed, before they are auto-removed by apt on classic installs. Historically the installation was optimized for metered download size only. However, kernel size growth and usage no longer warrant such optimizations. During the 23.10 Mantic Minatour cycle, I led a coordinated effort across multiple teams to implement lots of optimizations that together achieved unprecedented install footprint improvements.

Given a typical install of 3 generic kernel ABIs in the default configuration on a regular-sized VM (2 CPU cores 8GB of RAM) the following metrics are achieved in Ubuntu 23.10 versus Ubuntu 22.04 LTS:

• 2x less disk space used (1,417MB vs 2,940MB, including initrd)

• 3x less peak RAM usage for the initrd boot (68MB vs 204MB)

• 0.5x increase in download size (949MB vs 600MB)

• 2.5x faster initrd generation (4.5s vs 11.3s)

• approximately the same total time (103s vs 98s, hardware dependent)

For minimal cloud images that do not install either linux-firmware or modules extra the numbers are:

• 1.3x less disk space used (548MB vs 742MB)

• 2.2x less peak RAM usage for initrd boot (27MB vs 62MB)

• 0.4x increase in download size (207MB vs 146MB)

Hopefully, the compromise of download size, relative to the disk space & initrd savings is a win for the majority of platforms and use cases. For users on extremely expensive and metered connections, the likely best saving is to receive air-gapped updates or skip updates.

This was achieved by precompressing kernel modules & firmware files with the maximum level of Zstd compression at package build time; making actual .deb files uncompressed; assembling the initrd using split cpio archives - uncompressed for the pre-compressed files, whilst compressing only the userspace portions of the initrd; enabling in-kernel module decompression support with matching kmod; fixing bugs in all of the above, and landing all of these things in time for the feature freeze. Whilst leveraging the experience and some of the design choices implementations we have already been shipping on Ubuntu Core. Some of these changes are backported to Jammy, but only enough to support smooth upgrades to Mantic and later. Complete gains are only possible to experience on Mantic and later.

The discovered bugs in kernel module loading code likely affect systems that use LoadPin LSM with kernel space module uncompression as used on ChromeOS systems. Hopefully, Kees Cook or other ChromeOS developers pick up the kernel fixes from the stable trees. Or you know, just use Ubuntu kernels as they do get fixes and features like these first.

The team that designed and delivered these changes is large: Benjamin Drung, Andrea Righi, Juerg Haefliger, Julian Andres Klode, Steve Langasek, Michael Hudson-Doyle, Robert Kratky, Adrien Nader, Tim Gardner, Roxana Nicolescu - and myself Dimitri John Ledkov ensuring the most optimal solution is implemented, everything lands on time, and even implementing portions of the final solution.

Hi, It's me, I am a Staff Engineer at Canonical and we are hiring https://canonical.com/careers.

Lots of additional technical details and benchmarks on a huge range of diverse hardware and architectures, and bikeshedding all the things below:

• https://lists.ubuntu.com/archives/ubuntu-devel/2023-July/thread.html#42652
• https://lists.ubuntu.com/archives/kernel-team/2023-July/thread.html#141412
• https://lists.ubuntu.com/archives/ubuntu-devel/2023-July/thread.html#42707
• https://discourse.ubuntu.com/t/reduce-initramfs-size-and-speed-up-the-generation-in-ubuntu-23-10/38972
• https://lore.kernel.org/all/20230830155820.138178-1-andrea.righi@canonical.com/
• https://lore.kernel.org/all/20230829123808.325202-1-andrea.righi@canonical.com/
• https://facebook.github.io/zstd/

For questions and comments please post to Kernel section on Ubuntu Discourse.

Welcome to the September 2023 report from the Reproducible Builds project In these reports, we outline the most important things that we have been up to over the past month. As a quick recap, whilst anyone may inspect the source code of free software for malicious flaws, almost all software is distributed to end users as pre-compiled binaries.
Andreas Herrmann gave a talk at All Systems Go 2023 titled Fast, correct, reproducible builds with Nix and Bazel . Quoting from the talk description:

You will be introduced to Google s open source build system Bazel, and will learn how it provides fast builds, how correctness and reproducibility is relevant, and how Bazel tries to ensure correctness. But, we will also see where Bazel falls short in ensuring correctness and reproducibility. You will [also] learn about the purely functional package manager Nix and how it approaches correctness and build isolation. And we will see where Bazel has an advantage over Nix when it comes to providing fast feedback during development.

Andreas also shows how you can get the best of both worlds and combine Nix and Bazel, too. A video of the talk is available.
diffoscope is our in-depth and content-aware diff utility that can locate and diagnose reproducibility issues. This month, Chris Lamb fixed compatibility with file(1) version 5.45 [ ] and updated some documentation [ ]. In addition, Vagrant Cascadian extended support for GNU Guix [ ][ ] and updated the version in that distribution as well. [ ].
Yet another reminder that our upcoming Reproducible Builds Summit is set to take place from October 31st November 2nd 2023 in Hamburg, Germany. If you haven t been before, our summits are a unique gathering that brings together attendees from diverse projects, united by a shared vision of advancing the Reproducible Builds effort. During this enriching event, participants will have the opportunity to engage in discussions, establish connections and exchange ideas to drive progress in this vital field. If you re interested in joining us this year, please make sure to read the event page, the news item, or the invitation email that Mattia Rizzolo sent out recently, all of which have more details about the event and location. We are also still looking for sponsors to support the event, so please reach out to the organising team if you are able to help. Also note that PackagingCon 2023 is taking place in Berlin just before our summit.
On the Reproducible Builds website, Greg Chabala updated the JVM-related documentation to update a link to the BUILDSPEC.md file. [ ] And Fay Stegerman fixed the builds failing because of a YAML syntax error.

Distribution work In Debian, this month:

• Debian bug #940234 was originally opened in September 2019 by Aurelien Jarno to request that Debian add a new requirement that repeatedly building the source package in the same environment produces identical .dsc file modulo the GPG signature . This month, however, Russ Allbery closed the bug due to concerns about the viability of source reproducibility.
• 10 reviews of Debian packages were added, 56 were updated and 68 were removed this month adding to our knowledge about identified issues.
• Bastian Blank posted a mail to a number of Debian mailing lists titled Upcoming changes to Debian Linux kernel packages . Under Kernel modules will be signed with an ephemeral key, Bastian wrote: Yes, this will make the build unreproducible, but no better solution currently exists.
• Vagrant Cascadian posted about various experiments with verification builds for Debian and snapshotting the Debian archive

September saw F-Droid add ten new reproducible apps, and one existing app switched to reproducible builds. In addition, two reproducible apps were archived and one was disabled for a current total of 199 apps published with Reproducible Builds and using the upstream developer s signature. [ ] In addition, an extensive blog post was posted on f-droid.org titled Reproducible builds, signing keys, and binary repos .

Upstream patches The Reproducible Builds project detects, dissects and attempts to fix as many currently-unreproducible packages as possible. We endeavour to send all of our patches upstream where appropriate. This month, we wrote a large number of such patches, including:

• openSUSE monthly
• Bernhard M. Wiedemann:
  • linuxsampler (benchmarking issue)
  • antlr3 (date)
  • rpm (embeds too many build details)
  • seamonkey (date)
  • conky (date and ordering-related issue)
  • lsp-plugins-shared (date/copyright year issue)
  • build-compare
  • helix (ASLR-related non-determinism)
  • intel-graphics-compiler (ASLR)
• Chris Lamb:
  • #1052950 filed against sphinxcontrib-mermaid.
  • #1052970 filed against mkdocs-material.
  • #1052989 filed against apophenia.
  • #1053205 filed against lapackpp.
  • #1053263 filed against blaspp.
• Fridrich Strba applied 124 Java-related patches into openSUSE:
  • mysql-connector-java, java-21-openjdk, apache-ivy, maven-assembly-plugin, eclipse, antlr3, groovy18, hbci4java, ini4j, hppc, checkstyle, glassfish-jaxb, tycho, xmvn, mockito, languagetool, json-lib, jnr-unixsocket, jnr-ffi, jnr-enxio, jboss-jaxrs-2.0-api, istack-commons, rxtx-java, glassfish-jaxb, glassfish-hk2, findbugs, docker-client-java, maven, xmvn-connector-ivy, xmlstreambuffer, checkstyle, cglib, bean-validation-api, aws-sdk-java, javapackages-tools, ant, scala, osgi-service-log, jmdns, xml-security, super-csv, osgi-service-jdbc, msv, junit5, jsr-311, jersey, itextpdf, httpcomponents-asyncclient, ed25519-java, jnacl, javaparser, picocli, freemarker, extra166y, javaparser, xstream, woodstox-core, uom-lib, unit-api, uncommons-maths, tycho, treelayout, tiger-types, super-csv, stax-ex, stax2-api, sqlite-jdbc, reflectasm, prometheus-simpleclient-java, powermock, paranamer, opennlp, netty3, mybatis, morfologik-stemming, minlog, maven-archetype, mariadb-java-client, logback, kryo, jsonp, jopt-simple, jnr-posix, jnr-constants, jnr-a64asm, jfreechart, jffi, jetty-schemas, jetty-minimal, jeromq, jctools, jcsp, jboss-websocket-1.0-api, jboss-marshalling, jboss-logmanager, jboss-logging, javaewah, jatl, janino, jackson-modules-base, jackson-jaxrs-providers, jackson-datatypes-collections, jackson-dataformat-xml, jackson-dataformats-text, jackson-dataformats-binary, indriya, google-gson, glassfish-websocket-api, glassfish-transaction-api, glassfish-jsp, glassfish-jax-rs-api, glassfish-hk2, glassfish-fastinfoset, felix-scr, felix-gogo-shell, felix-gogo-command, disruptor, apache-commons-ognl, apache-commons-math, apache-commons-csv, antlr4, jettison, sisu, maven
• Pol Dellaiera:
  • Since version 2.6.4, Composer (the PHP package manager) is now fully reproducible. See the work in the corresponding PR.

Testing framework The Reproducible Builds project operates a comprehensive testing framework (available at tests.reproducible-builds.org) in order to check packages and other artifacts for reproducibility. In August, a number of changes were made by Holger Levsen:

• Disable armhf and i386 builds due to Debian bug #1052257. [ ][ ][ ][ ]
• Run diffoscope with a lower ionice priority. [ ]
• Log every build in a simple text file [ ] and create persistent stamp files when running diffoscope to ease debugging [ ].
• Run schedulers one hour after dinstall again. [ ]
• Temporarily use diffoscope from the host, and not from a schroot running the tested suite. [ ][ ]
• Fail the diffoscope distribution test if the diffoscope version cannot be determined. [ ]
• Fix a spelling error in the email to IRC gateway. [ ]
• Force (and document) the reconfiguration of all jobs, due to the recent rise of zombies. [ ][ ][ ][ ]
• Deal with a rare condition when killing processes which should not be there. [ ]
• Install the Debian backports kernel in an attempt to address Debian bug #1052257. [ ][ ]

In addition, Mattia Rizzolo fixed a call to diffoscope --version (as suggested by Fay Stegerman on our mailing list) [ ], worked on an openQA credential issue [ ] and also made some changes to the machine-readable reproducible metadata, reproducible-tracker.json [ ]. Lastly, Roland Clobus added instructions for manual configuration of the openQA secrets [ ].

---

If you are interested in contributing to the Reproducible Builds project, please visit our Contribute page on our website. However, you can get in touch with us via:

• IRC: #reproducible-builds on irc.oftc.net.
• Mailing list: rb-general@lists.reproducible-builds.org
• Mastodon: @reproducible_builds
• Twitter: @ReproBuilds

Official logo of DebConf23

Introduction DebConf23, the 24th annual Debian Conference, was held in India in the city of Kochi, Kerala from the 3rd to the 17th of September, 2023. Ever since I got to know about it (which was more than an year ago), I was excited to attend DebConf in my home country. This was my second DebConf, as I attended one last year in Kosovo. I was very happy that I didn t need to apply for a visa to attend. I got full bursary to attend the event (thanks a lot to Debian for that!) which is always helpful in covering the expenses, especially if the venue is a five star hotel :) For the conference, I submitted two talks. One was suggested by Sahil on Debian packaging for beginners, while the other was suggested by Praveen who opined that a talk covering broader topics about freedom in self-hosting services will be better, when I started discussing about submitting a talk about prav app project. So I submitted one on Debian packaging for beginners and the other on ideas on sustainable solutions for self-hosting. My friend Suresh - who is enthusiastic about Debian and free software - wanted to attend the DebConf as well. When the registration started, I reminded him about applying. We landed in Kochi on the 28th of August 2023 during the festival of Onam. We celebrated Onam in Kochi, had a trip to Wayanad, and returned to Kochi. On the evening of the 3rd of September, we reached the venue - Four Points Hotel by Sheraton, at Infopark Kochi, Ernakulam, Kerala, India.

Suresh and me celebrating Onam in Kochi.

Hotel overview The hotel had 14 floors, and featured a swimming pool and gym (these were included in our package). The hotel gave us elevator access for only our floor, along with public spaces like the reception, gym, swimming pool, and dining areas. The temperature inside the hotel was pretty cold and I had to buy a jacket to survive. Perhaps the hotel was in cahoots with winterwear companies? :)

Four Points Hotel by Sheraton was the venue of DebConf23. Photo credits: Bilal

Photo of the pool. Photo credits: Andreas Tille.

View from the hotel window.

Meals On the first day, Suresh and I had dinner at the eatery on the third floor. At the entrance, a member of the hotel staff asked us about how many people we wanted a table for. I told her that it s just the two of us at the moment, but (as we are attending a conference) we might be joined by others. Regardless, they gave us a table for just two. Within a few minutes, we were joined by Alper from Turkey and urbec from Germany. So we shifted to a larger table but then we were joined by even more people, so we were busy adding more chairs to our table. urbec had already been in Kerala for the past 5-6 days and was, on one hand, very happy already with the quality and taste of bananas in Kerala and on the other, rather afraid of the spicy food :) Two days later, the lunch and dinner were shifted to the All Spice Restaurant on the 14th floor, but the breakfast was still served at the eatery. Since the eatery (on the 3rd floor) had greater variety of food than the other venue, this move made breakfast the best meal for me and many others. Many attendees from outside India were not accustomed to the spicy food. It is difficult for locals to help them, because what we consider mild can be spicy for others. It is not easy to satisfy everyone at the dining table, but I think the organizing team did a very good job in the food department. (That said, it didn t matter for me after a point, and you will know why.) The pappadam were really good, and I liked the rice labelled Kerala rice . I actually brought that exact rice and pappadam home during my last trip to Kochi and everyone at my home liked it too (thanks to Abhijit PA). I also wished to eat all types of payasams from Kerala and this really happened (thanks to Sruthi who designed the menu). Every meal had a different variety of payasam and it was awesome, although I didn t like some of them, mostly because they were very sweet. Meals were later shifted to the ground floor (taking away the best breakfast option which was the eatery).

This place served as lunch and dinner place and later as hacklab during debconf. Photo credits: Bilal

The excellent Swag Bag The DebConf registration desk was at the second floor. We were given a very nice swag bag. They were available in multiple colors - grey, green, blue, red - and included an umbrella, a steel mug, a multiboot USB drive by Mostly Harmless, a thermal flask, a mug by Canonical, a paper coaster, and stickers. It rained almost every day in Kochi during our stay, so handing out an umbrella to every attendee was a good idea.

Picture of the awesome swag bag given at DebConf23. Photo credits: Ravi Dwivedi

A gift for Nattie During breakfast one day, Nattie (Belgium) expressed the desire to buy a coffee filter. The next time I went to the market, I bought a coffee filter for her as a gift. She seemed happy with the gift and was flattered to receive a gift from a young man :)

Being a mentor There were many newbies who were eager to learn and contribute to Debian. So, I mentored whoever came to me and was interested in learning. I conducted a packaging workshop in the bootcamp, but could only cover how to set up the Debian Unstable environment, and had to leave out how to package (but I covered that in my talk). Carlos (Brazil) gave a keysigning session in the bootcamp. Praveen was also mentoring in the bootcamp. I helped people understand why we sign GPG keys and how to sign them. I planned to take a workshop on it but cancelled it later.

My talk My Debian packaging talk was on the 10th of September, 2023. I had not prepared slides for my Debian packaging talk in advance - I thought that I could do it during the trip, but I didn t get the time so I prepared them on the day before the talk. Since it was mostly a tutorial, the slides did not need much preparation. My thanks to Suresh, who helped me with the slides and made it possible to complete them in such a short time frame. My talk was well-received by the audience, going by their comments. I am glad that I could give an interesting presentation.

My presentation photo. Photo credits: Valessio

Visiting a saree shop After my talk, Suresh, Alper, and I went with Anisa and Kristi - who are both from Albania, and have a never-ending fascination for Indian culture :) - to buy them sarees. We took autos to Kakkanad market and found a shop with a great variety of sarees. I was slightly familiar with the area around the hotel, as I had been there for a week. Indian women usually don t try on sarees while buying - they just select the design. But Anisa wanted to put one on and take a few photos as well. The shop staff did not have a trial saree for this purpose, so they took a saree from a mannequin. It took about an hour for the lady at the shop to help Anisa put on that saree but you could tell that she was in heaven wearing that saree, and she bought it immediately :) Alper also bought a saree to take back to Turkey for his mother. Me and Suresh wanted to buy a kurta which would go well with the mundu we already had, but we could not find anything to our liking.

Selfie with Anisa and Kristi. Photo credits: Anisa.

Cheese and Wine Party On the 11th of September we had the Cheese and Wine Party, a tradition of every DebConf. I brought Kaju Samosa and Nankhatai from home. Many attendees expressed their appreciation for the samosas. During the party, I was with Abhas and had a lot of fun. Abhas brought packets of paan and served them at the Cheese and Wine Party. We discussed interesting things and ate burgers. But due to the restrictive alcohol laws in the state, it was less fun compared to the previous DebConfs - you could only drink alcohol served by the hotel in public places. If you bought your own alcohol, you could only drink in private places (such as in your room, or a friend s room), but not in public places.

Me helping with the Cheese and Wine Party.

Party at my room Last year, Joenio (Brazilian) brought pastis from France which I liked. He brought the same alocholic drink this year too. So I invited him to my room after the Cheese and Wine party to have pastis. My idea was to have them with my roommate Suresh and Joenio. But then we permitted Joenio to bring as many people as he wanted and he ended up bringing some ten people. Suddenly, the room was crowded. I was having good time at the party, serving them the snacks given to me by Abhas. The news of an alcohol party at my room spread like wildfire. Soon there were so many people that the AC became ineffective and I found myself sweating. I left the room and roamed around in the hotel for some fresh air. I came back after about 1.5 hours - for most part, I was sitting at the ground floor with TK Saurabh. And then I met Abraham near the gym (which was my last meeting with him). I came back to my room at around 2:30 AM. Nobody seemed to have realized that I was gone. They were thanking me for hosting such a good party. A lot of people left at that point and the remaining people were playing songs and dancing (everyone was dancing all along!). I had no energy left to dance and to join them. They left around 03:00 AM. But I am glad that people enjoyed partying in my room.

This picture was taken when there were few people in my room for the party.

Sadhya Thali On the 12th of September, we had a sadhya thali for lunch. It is a vegetarian thali served on a banana leaf on the eve of Thiruvonam. It wasn t Thiruvonam on this day, but we got a special and filling lunch. The rasam and payasam were especially yummy.

Sadhya Thali: A vegetarian meal served on banana leaf. Payasam and rasam were especially yummy! Photo credits: Ravi Dwivedi.

Sadhya thali being served at debconf23. Photo credits: Bilal

Day trip On the 13th of September, we had a daytrip. I chose the daytrip houseboat in Allepey. Suresh chose the same, and we registered for it as soon as it was open. This was the most sought-after daytrip by the DebConf attendees - around 80 people registered for it. Our bus was set to leave at 9 AM on the 13th of September. Me and Suresh woke up at 8:40 and hurried to get to the bus in time. It took two hours to reach the venue where we get the houseboat. The houseboat experience was good. The trip featured some good scenery. I got to experience the renowned Kerala backwaters. We were served food on the boat. We also stopped at a place and had coconut water. By evening, we came back to the place where we had boarded the boat.

Group photo of our daytrip. Photo credits: Radhika Jhalani

A good friend lost When we came back from the daytrip, we received news that Abhraham Raji was involved in a fatal accident during a kayaking trip. Abraham Raji was a very good friend of mine. In my Albania-Kosovo-Dubai trip last year, he was my roommate at our Tirana apartment. I roamed around in Dubai with him, and we had many discussions during DebConf22 Kosovo. He was the one who took the photo of me on my homepage. I also met him in MiniDebConf22 Palakkad and MiniDebConf23 Tamil Nadu, and went to his flat in Kochi this year in June. We had many projects in common. He was a Free Software activist and was the designer of the DebConf23 logo, in addition to those for other Debian events in India.

A selfie in memory of Abraham.

We were all fairly shocked by the news. I was devastated. Food lost its taste, and it became difficult to sleep. That night, Anisa and Kristi cheered me up and gave me company. Thanks a lot to them. The next day, Joenio also tried to console me. I thank him for doing a great job. I thank everyone who helped me in coping with the difficult situation. On the next day (the 14th of September), the Debian project leader Jonathan Carter addressed and announced the news officially. THe Debian project also mentioned it on their website. Abraham was supposed to give a talk, but following the incident, all talks were cancelled for the day. The conference dinner was also cancelled. As I write, 9 days have passed since his death, but even now I cannot come to terms with it.

Visiting Abraham s house On the 15th of September, the conference ran two buses from the hotel to Abraham s house in Kottayam (2 hours ride). I hopped in the first bus and my mood was not very good. Evangelos (Germany) was sitting opposite me, and he began conversing with me. The distraction helped and I was back to normal for a while. Thanks to Evangelos as he supported me a lot on that trip. He was also very impressed by my use of the StreetComplete app which I was using to edit OpenStreetMap. In two hours, we reached Abraham s house. I couldn t control myself and burst into tears. I went to see the body. I met his family (mother, father and sister), but I had nothing to say and I felt helpless. Owing to the loss of sleep and appetite over the past few days, I had no energy, and didn t think it was good idea for me to stay there. I went back by taking the bus after one hour and had lunch at the hotel. I withdrew my talk scheduled for the 16th of September.

A Japanese gift I got a nice Japanese gift from Niibe Yutaka (Japan) - a folder to keep papers which had ancient Japanese manga characters. He said he felt guilty as he swapped his talk with me and so it got rescheduled from 12th September to 16 September which I withdrew later.

Thanks to Niibe Yutaka (the person towards your right hand) from Japan (FSIJ), who gave me a wonderful Japanese gift during debconf23: A folder to keep pages with ancient Japanese manga characters printed on it. I realized I immediately needed that :)

This is the Japanese gift I received.

Group photo On the 16th of September, we had a group photo. I am glad that this year I was more clear in this picture than in DebConf22.

Click to enlarge

Volunteer work and talks attended I attended the training session for the video team and worked as a camera operator. The Bits from DPL was nice. I enjoyed Abhas presentation on home automation. He basically demonstrated how he liberated Internet-enabled home devices. I also liked Kristi s presentation on ways to engage with the GNOME community.

Bits from the DPL. Photo credits: Bilal

Kristi on GNOME community. Photo credits: Ravi Dwivedi.

Abhas' talk on home automation. Photo credits: Ravi Dwivedi.

I also attended lightning talks on the last day. Badri, Wouter, and I gave a demo on how to register on the Prav app. Prav got a fair share of advertising during the last few days.

I was roaming around with a QR code on my T-shirt for downloading Prav.

The night of the 17th of September Suresh left the hotel and Badri joined me in my room. Thanks to the efforts of Abhijit PA, Kiran, and Ananthu, I wore a mundu.

Me in mundu. Picture credits: Abhijith PA

I then joined Kalyani, Mangesh, Ruchika, Anisa, Ananthu and Kiran. We took pictures and this marked the last night of DebConf23.

Departure day The 18th of September was the day of departure. Badri slept in my room and left early morning (06:30 AM). I dropped him off at the hotel gate. The breakfast was at the eatery (3rd floor) again, and it was good. Sahil, Saswata, Nilesh, and I hung out on the ground floor.

From left: Nilesh, Saswata, me, Sahil. Photo credits: Sahil.

I had an 8 PM flight from Kochi to Delhi, for which I took a cab with Rhonda (Austria), Michael (Nigeria) and Yash (India). We were joined by other DebConf23 attendees at the Kochi airport, where we took another selfie.

Ruchika (taking the selfie) and from left to right: Yash, Joost (Netherlands), me, Rhonda

Joost and I were on the same flight, and we sat next to each other. He then took a connecting flight from Delhi to Netherlands, while I went with Yash to the New Delhi Railway Station, where we took our respective trains. I reached home on the morning of the 19th of September, 2023.

Joost and me going to Delhi. Photo credits: Ravi.

Big thanks to the organizers DebConf23 was hard to organize - strict alcohol laws, weird hotel rules, death of a close friend (almost a family member), and a scary notice by the immigration bureau. The people from the team are my close friends and I am proud of them for organizing such a good event. None of this would have been possible without the organizers who put more than a year-long voluntary effort to produce this. In the meanwhile, many of them had organized local events in the time leading up to DebConf. Kudos to them. The organizers also tried their best to get clearance for countries not approved by the ministry. I am also sad that people from China, Kosovo, and Iran could not join. In particular, I feel bad for people from Kosovo who wanted to attend but could not (as India does not consider their passport to be a valid travel document), considering how we Indians were so well-received in their country last year.

Note about myself I am writing this on the 22nd of September, 2023. It took me three days to put up this post - this was one of the tragic and hard posts for me to write. I have literally forced myself to write this. I have still not recovered from the loss of my friend. Thanks a lot to all those who helped me. PS: Credits to contrapunctus for making grammar, phrasing, and capitalization changes.

Contributing to Debian is part of Freexian s mission. This article covers the latest achievements of Freexian and their collaborators. All of this is made possible by organizations subscribing to our Long Term Support contracts and consulting services.

/usr-merge, by Helmut Grohne, et al Towards the end of April, the discussion on DEP 17 on debian-devel@l.d.o initiated by Helmut Grohne took off, trying to deal with the fact that while Debian bookworm has a merged /usr, files are still being distributed to / and /usr in Debian binary packages, and moving them currently has some risk of breakage. Most participants of the discussion agreed that files should be moved, and there are several competing design ideas for doing it safely. Most of the time was spent understanding the practical implications of lifting the moratorium and moving all the files from / to /usr in a coordinated effort. With help from Emilio Pozuelo Monfort, Enrico Zini, and Raphael Hertzog, Helmut Grohne performed extensive analysis of the various aspects, including quantitative analysis of the original file move problem, analysis of effects on dpkg-divert, dpkg-statoverride, and update-alternatives, analysis of effects on filesystem bootstrapping tools. Most of the problematic cases spawned plausible workarounds, such as turning Breaks into Conflicts in selected cases or adding protective diversions for the symbolic links that enable aliasing. Towards the end of May, Andreas Beckmann reported a new failure scenario which may cause shared resources to inadvertently disappear, such as directories and even regular files in case of Multi-Arch packages, and our work on analyzing these problems and proposing mitigations is on-going. While the quantitative analysis is funded by Freexian, we wouldn t be here without the extensive feedback and ideas of many voluntary contributors from multiple areas of Debian, which are too many to name here. Thank you.

Preparing for the tox 4 transition, by Stefano Rivera While Debian was in freeze for the bookworm release, tox 4 has landed in Debian experimental, and some packages are starting to require it, upstream. It has some backwards-incompatible behavior that breaks many packages using tox through pybuild. So Stefano had to make some changes to pybuild and to many packages that run build-time tests with tox. The easy bits of this transition are now completed in git / experimental, but a few packages that integrate deeply into tox need upstream work.

Debian Printing, by Thorsten Alteholz Just before the release of Bookworm, lots of QA tools were used to inspect packages. One of these tools found a systemd service file in a wrong directory. So, Thorsten did another upload of package lprint to correct this. Thanks a lot to all the hardworking people who run such tools and file bugs. Thorsten also participated in discussions about the new Common Printing Dialog Backends (CPDB) that will be introduced in Trixie and hopefully can replace the current printing architecture in Forky.

Miscellaneous contributions

• DebConf 23 preparations by Stefano Rivera. Some work on the website, video team planning, accounting, and team documentation.
• Utkarsh Gupta started to prep the work on the bursary team s side for DC23.
• Stefano spun up a website for the Hamburg mini-DebConf so that the video team could have a machine-readable schedule and a place to stream video from the event.
• Santiago Ruano Rinc n reviewed and sponsored four python packages of a prospective Debian member.
• Helmut Grohne supported Timo Roehling and Jochen Sprickerhof to improve cross building in 15 ROS packages.
• Helmut Grohne supported Jochen Sprickerhof with diagnosing an e2fsprogs RC bug.
• Helmut Grohne continued to maintain rebootstrap and located an issue with lto in gcc-13.
• Anton Gladky fixed some RC-Bugs and uploaded a new stravalib python library.

I watched a 2015 video from Andreas Schiffler the other day, where he set up LinuxCNC to send status information to the MQTT broker IBM Bluemix. As I also use MQTT for graphing, it occured to me that a generic MQTT LinuxCNC component would be useful and I set out to implement it. Today I got the first draft limping along and submitted as a patch to the LinuxCNC project. The simple part was setting up the MQTT publishing code in Python. I already have set up other parts submitting data to my Mosquito MQTT broker, so I could reuse that code. Writing a LinuxCNC component in Python as new to me, but using existing examples in the code repository and the extensive documentation, this was fairly straight forward. The hardest part was creating a automated test for the component to ensure it was working. Testing it in a simulated LinuxCNC machine proved very useful, as I discovered features I needed that I had not thought of yet, and adjusted the code quite a bit to make it easier to test without a operational MQTT broker available. The draft is ready and working, but I am unsure which LinuxCNC HAL pins I should collect and publish by default (in other words, the default set of information pieces published), and how to get the machine name from the LinuxCNC INI file. The latter is a minor detail, but I expect it would be useful in a setup with several machines available. I am hoping for feedback from the experienced LinuxCNC developers and users, to make the component even better before it can go into the mainland LinuxCNC code base. Since I started on the MQTT component, I came across another video from Kent VanderVelden where he combine LinuxCNC with a set of screen glasses controlled by a Raspberry Pi, and it occured to me that it would be useful for such use cases if LinuxCNC also provided a REST API for querying its status. I hope to start on such component once the MQTT component is working well. As usual, if you use Bitcoin and want to show your support of my activities, please send Bitcoin donations to my address 15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b.

In my tubman setup, I started using ZFS on an old server I had lying around. The machine is really old though (2011!) and it "feels" pretty slow. I want to see how much of that is ZFS and how much is the machine. Synthetic benchmarks show that ZFS may be slower than mdadm in RAID-10 or RAID-6 configuration, so I want to confirm that on a live workload: my workstation. Plus, I want easy, regular, high performance backups (with send/receive snapshots) and there's no way I'm going to use BTRFS because I find it too confusing and unreliable. So off we go.

Installation Since this is a conversion (and not a new install), our procedure is slightly different than the official documentation but otherwise it's pretty much in the same spirit: we're going to use ZFS for everything, including the root filesystem. So, install the required packages, on the current system:

apt install --yes gdisk zfs-dkms zfs zfs-initramfs zfsutils-linux

We also tell DKMS that we need to rebuild the initrd when upgrading:

echo REMAKE_INITRD=yes > /etc/dkms/zfs.conf

Partitioning This is going to partition /dev/sdc with:

• 1MB MBR / BIOS legacy boot
• 512MB EFI boot
• 1GB bpool, unencrypted pool for /boot
• rest of the disk for zpool, the rest of the data

   sgdisk --zap-all /dev/sdc
   sgdisk -a1 -n1:24K:+1000K -t1:EF02 /dev/sdc
   sgdisk     -n2:1M:+512M   -t2:EF00 /dev/sdc
   sgdisk     -n3:0:+1G      -t3:BF01 /dev/sdc
   sgdisk     -n4:0:0        -t4:BF00 /dev/sdc
  

That will look something like this:

    root@curie:/home/anarcat# sgdisk -p /dev/sdc
    Disk /dev/sdc: 1953525168 sectors, 931.5 GiB
    Model: ESD-S1C         
    Sector size (logical/physical): 512/512 bytes
    Disk identifier (GUID): [REDACTED]
    Partition table holds up to 128 entries
    Main partition table begins at sector 2 and ends at sector 33
    First usable sector is 34, last usable sector is 1953525134
    Partitions will be aligned on 16-sector boundaries
    Total free space is 14 sectors (7.0 KiB)
    Number  Start (sector)    End (sector)  Size       Code  Name
       1              48            2047   1000.0 KiB  EF02  
       2            2048         1050623   512.0 MiB   EF00  
       3         1050624         3147775   1024.0 MiB  BF01  
       4         3147776      1953525134   930.0 GiB   BF00

Unfortunately, we can't be sure of the sector size here, because the USB controller is probably lying to us about it. Normally, this smartctl command should tell us the sector size as well:

root@curie:~# smartctl -i /dev/sdb -qnoserial
smartctl 7.2 2020-12-30 r5155 [x86_64-linux-5.10.0-14-amd64] (local build)
Copyright (C) 2002-20, Bruce Allen, Christian Franke, www.smartmontools.org
=== START OF INFORMATION SECTION ===
Model Family:     Western Digital Black Mobile
Device Model:     WDC WD10JPLX-00MBPT0
Firmware Version: 01.01H01
User Capacity:    1 000 204 886 016 bytes [1,00 TB]
Sector Sizes:     512 bytes logical, 4096 bytes physical
Rotation Rate:    7200 rpm
Form Factor:      2.5 inches
Device is:        In smartctl database [for details use: -P show]
ATA Version is:   ATA8-ACS T13/1699-D revision 6
SATA Version is:  SATA 3.0, 6.0 Gb/s (current: 6.0 Gb/s)
Local Time is:    Tue May 17 13:33:04 2022 EDT
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

Above is the example of the builtin HDD drive. But the SSD device enclosed in that USB controller doesn't support SMART commands, so we can't trust that it really has 512 bytes sectors. This matters because we need to tweak the ashift value correctly. We're going to go ahead the SSD drive has the common 4KB settings, which means ashift=12. Note here that we are not creating a separate partition for swap. Swap on ZFS volumes (AKA "swap on ZVOL") can trigger lockups and that issue is still not fixed upstream. Ubuntu recommends using a separate partition for swap instead. But since this is "just" a workstation, we're betting that we will not suffer from this problem, after hearing a report from another Debian developer running this setup on their workstation successfully. We do not recommend this setup though. In fact, if I were to redo this partition scheme, I would probably use LUKS encryption and setup a dedicated swap partition, as I had problems with ZFS encryption as well.

Creating pools ZFS pools are somewhat like "volume groups" if you are familiar with LVM, except they obviously also do things like RAID-10. (Even though LVM can technically also do RAID, people typically use mdadm instead.) In any case, the guide suggests creating two different pools here: one, in cleartext, for boot, and a separate, encrypted one, for the rest. Technically, the boot partition is required because the Grub bootloader only supports readonly ZFS pools, from what I understand. But I'm a little out of my depth here and just following the guide.

Boot pool creation This creates the boot pool in readonly mode with features that grub supports:

    zpool create \
        -o cachefile=/etc/zfs/zpool.cache \
        -o ashift=12 -d \
        -o feature@async_destroy=enabled \
        -o feature@bookmarks=enabled \
        -o feature@embedded_data=enabled \
        -o feature@empty_bpobj=enabled \
        -o feature@enabled_txg=enabled \
        -o feature@extensible_dataset=enabled \
        -o feature@filesystem_limits=enabled \
        -o feature@hole_birth=enabled \
        -o feature@large_blocks=enabled \
        -o feature@lz4_compress=enabled \
        -o feature@spacemap_histogram=enabled \
        -o feature@zpool_checkpoint=enabled \
        -O acltype=posixacl -O canmount=off \
        -O compression=lz4 \
        -O devices=off -O normalization=formD -O relatime=on -O xattr=sa \
        -O mountpoint=/boot -R /mnt \
        bpool /dev/sdc3

I haven't investigated all those settings and just trust the upstream guide on the above.

Main pool creation This is a more typical pool creation.

    zpool create \
        -o ashift=12 \
        -O encryption=on -O keylocation=prompt -O keyformat=passphrase \
        -O acltype=posixacl -O xattr=sa -O dnodesize=auto \
        -O compression=zstd \
        -O relatime=on \
        -O canmount=off \
        -O mountpoint=/ -R /mnt \
        rpool /dev/sdc4

Breaking this down:

• -o ashift=12: mentioned above, 4k sector size
• -O encryption=on -O keylocation=prompt -O keyformat=passphrase: encryption, prompt for a password, default algorithm is aes-256-gcm, explicit in the guide, made implicit here
• -O acltype=posixacl -O xattr=sa: enable ACLs, with better performance (not enabled by default)
• -O dnodesize=auto: related to extended attributes, less compatibility with other implementations
• -O compression=zstd: enable zstd compression, can be disabled/enabled by dataset to with zfs set compression=off rpool/example
• -O relatime=on: classic atime optimisation, another that could be used on a busy server is atime=off
• -O canmount=off: do not make the pool mount automatically with mount -a?
• -O mountpoint=/ -R /mnt: mount pool on / in the future, but /mnt for now

Those settings are all available in zfsprops(8). Other flags are defined in zpool-create(8). The reasoning behind them is also explained in the upstream guide and some also in [the Debian wiki][]. Those flags were actually not used:

• -O normalization=formD: normalize file names on comparisons (not storage), implies utf8only=on, which is a bad idea (and effectively meant my first sync failed to copy some files, including this folder from a supysonic checkout). and this cannot be changed after the filesystem is created. bad, bad, bad.

[the Debian wiki]: https://wiki.debian.org/ZFS#Advanced_Topics

Side note about single-disk pools Also note that we're living dangerously here: single-disk ZFS pools are rumoured to be more dangerous than not running ZFS at all. The choice quote from this article is:

[...] any error can be detected, but cannot be corrected. This sounds like an acceptable compromise, but its actually not. The reason its not is that ZFS' metadata cannot be allowed to be corrupted. If it is it is likely the zpool will be impossible to mount (and will probably crash the system once the corruption is found). So a couple of bad sectors in the right place will mean that all data on the zpool will be lost. Not some, all. Also there's no ZFS recovery tools, so you cannot recover any data on the drives.

Compared with (say) ext4, where a single disk error can recovered, this is pretty bad. But we are ready to live with this with the idea that we'll have hourly offline snapshots that we can easily recover from. It's trade-off. Also, we're running this on a NVMe/M.2 drive which typically just blinks out of existence completely, and doesn't "bit rot" the way a HDD would. Also, the FreeBSD handbook quick start doesn't have any warnings about their first example, which is with a single disk. So I am reassured at least.

Creating mount points Next we create the actual filesystems, known as "datasets" which are the things that get mounted on mountpoint and hold the actual files.

• this creates two containers, for ROOT and BOOT

   zfs create -o canmount=off -o mountpoint=none rpool/ROOT &&
   zfs create -o canmount=off -o mountpoint=none bpool/BOOT
  

  Note that it's unclear to me why those datasets are necessary, but they seem common practice, also used in this FreeBSD example. The OpenZFS guide mentions the Solaris upgrades and Ubuntu's zsys that use that container for upgrades and rollbacks. This blog post seems to explain a bit the layout behind the installer.
• this creates the actual boot and root filesystems:

   zfs create -o canmount=noauto -o mountpoint=/ rpool/ROOT/debian &&
   zfs mount rpool/ROOT/debian &&
   zfs create -o mountpoint=/boot bpool/BOOT/debian
  

  I guess the debian name here is because we could technically have multiple operating systems with the same underlying datasets.
• then the main datasets:

   zfs create                                 rpool/home &&
   zfs create -o mountpoint=/root             rpool/home/root &&
   chmod 700 /mnt/root &&
   zfs create                                 rpool/var
  

• exclude temporary files from snapshots:

   zfs create -o com.sun:auto-snapshot=false  rpool/var/cache &&
   zfs create -o com.sun:auto-snapshot=false  rpool/var/tmp &&
   chmod 1777 /mnt/var/tmp
  

• and skip automatic snapshots in Docker:

   zfs create -o canmount=off                 rpool/var/lib &&
   zfs create -o com.sun:auto-snapshot=false  rpool/var/lib/docker
  

  Notice here a peculiarity: we must create rpool/var/lib to create rpool/var/lib/docker otherwise we get this error:

   cannot create 'rpool/var/lib/docker': parent does not exist
  

  ... and no, just creating /mnt/var/lib doesn't fix that problem. In fact, it makes things even more confusing because an existing directory shadows a mountpoint, which is the opposite of how things normally work. Also note that you will probably need to change storage driver in Docker, see the zfs-driver documentation for details but, basically, I did:

  echo '  "storage-driver": "zfs"  ' > /etc/docker/daemon.json
  

  Note that podman has the same problem (and similar solution):

  printf '[storage]\ndriver = "zfs"\n' > /etc/containers/storage.conf
  

• make a tmpfs for /run:

   mkdir /mnt/run &&
   mount -t tmpfs tmpfs /mnt/run &&
   mkdir /mnt/run/lock
  

We don't create a /srv, as that's the HDD stuff. Also mount the EFI partition:

mkfs.fat -F 32 /dev/sdc2 &&
mount /dev/sdc2 /mnt/boot/efi/

At this point, everything should be mounted in /mnt. It should look like this:

root@curie:~# LANG=C df -h -t zfs -t vfat
Filesystem            Size  Used Avail Use% Mounted on
rpool/ROOT/debian     899G  384K  899G   1% /mnt
bpool/BOOT/debian     832M  123M  709M  15% /mnt/boot
rpool/home            899G  256K  899G   1% /mnt/home
rpool/home/root       899G  256K  899G   1% /mnt/root
rpool/var             899G  384K  899G   1% /mnt/var
rpool/var/cache       899G  256K  899G   1% /mnt/var/cache
rpool/var/tmp         899G  256K  899G   1% /mnt/var/tmp
rpool/var/lib/docker  899G  256K  899G   1% /mnt/var/lib/docker
/dev/sdc2             511M  4.0K  511M   1% /mnt/boot/efi

Now that we have everything setup and mounted, let's copy all files over.

Copying files This is a list of all the mounted filesystems

for fs in /boot/ /boot/efi/ / /home/; do
    echo "syncing $fs to /mnt$fs..." && 
    rsync -aSHAXx --info=progress2 --delete $fs /mnt$fs
done

You can check that the list is correct with:

mount -l -t ext4,btrfs,vfat   awk ' print $3 '

Note that we skip /srv as it's on a different disk. On the first run, we had:

root@curie:~# for fs in /boot/ /boot/efi/ / /home/; do
        echo "syncing $fs to /mnt$fs..." && 
        rsync -aSHAXx --info=progress2 $fs /mnt$fs
    done
syncing /boot/ to /mnt/boot/...
              0   0%    0.00kB/s    0:00:00 (xfr#0, to-chk=0/299)  
syncing /boot/efi/ to /mnt/boot/efi/...
     16,831,437 100%  184.14MB/s    0:00:00 (xfr#101, to-chk=0/110)
syncing / to /mnt/...
 28,019,293,280  94%   47.63MB/s    0:09:21 (xfr#703710, ir-chk=6748/839220)rsync: [generator] delete_file: rmdir(var/lib/docker) failed: Device or resource busy (16)
could not make way for new symlink: var/lib/docker
 34,081,267,990  98%   50.71MB/s    0:10:40 (xfr#736577, to-chk=0/867732)    
rsync error: some files/attrs were not transferred (see previous errors) (code 23) at main.c(1333) [sender=3.2.3]
syncing /home/ to /mnt/home/...
rsync: [sender] readlink_stat("/home/anarcat/.fuse") failed: Permission denied (13)
 24,456,268,098  98%   68.03MB/s    0:05:42 (xfr#159867, ir-chk=6875/172377) 
file has vanished: "/home/anarcat/.cache/mozilla/firefox/s2hwvqbu.quantum/cache2/entries/B3AB0CDA9C4454B3C1197E5A22669DF8EE849D90"
199,762,528,125  93%   74.82MB/s    0:42:26 (xfr#1437846, ir-chk=1018/1983979)rsync: [generator] recv_generator: mkdir "/mnt/home/anarcat/dist/supysonic/tests/assets/\#346" failed: Invalid or incomplete multibyte or wide character (84)
*** Skipping any contents from this failed directory ***
315,384,723,978  96%   76.82MB/s    1:05:15 (xfr#2256473, to-chk=0/2993950)    
rsync error: some files/attrs were not transferred (see previous errors) (code 23) at main.c(1333) [sender=3.2.3]

Note the failure to transfer that supysonic file? It turns out they had a weird filename in their source tree, since then removed, but still it showed how the utf8only feature might not be such a bad idea. At this point, the procedure was restarted all the way back to "Creating pools", after unmounting all ZFS filesystems (umount /mnt/run /mnt/boot/efi && umount -t zfs -a) and destroying the pool, which, surprisingly, doesn't require any confirmation (zpool destroy rpool). The second run was cleaner:

root@curie:~# for fs in /boot/ /boot/efi/ / /home/; do
        echo "syncing $fs to /mnt$fs..." && 
        rsync -aSHAXx --info=progress2 --delete $fs /mnt$fs
    done
syncing /boot/ to /mnt/boot/...
              0   0%    0.00kB/s    0:00:00 (xfr#0, to-chk=0/299)  
syncing /boot/efi/ to /mnt/boot/efi/...
              0   0%    0.00kB/s    0:00:00 (xfr#0, to-chk=0/110)  
syncing / to /mnt/...
 28,019,033,070  97%   42.03MB/s    0:10:35 (xfr#703671, ir-chk=1093/833515)rsync: [generator] delete_file: rmdir(var/lib/docker) failed: Device or resource busy (16)
could not make way for new symlink: var/lib/docker
 34,081,807,102  98%   44.84MB/s    0:12:04 (xfr#736580, to-chk=0/867723)    
rsync error: some files/attrs were not transferred (see previous errors) (code 23) at main.c(1333) [sender=3.2.3]
syncing /home/ to /mnt/home/...
rsync: [sender] readlink_stat("/home/anarcat/.fuse") failed: Permission denied (13)
IO error encountered -- skipping file deletion
 24,043,086,450  96%   62.03MB/s    0:06:09 (xfr#151819, ir-chk=15117/172571)
file has vanished: "/home/anarcat/.cache/mozilla/firefox/s2hwvqbu.quantum/cache2/entries/4C1FDBFEA976FF924D062FB990B24B897A77B84B"
315,423,626,507  96%   67.09MB/s    1:14:43 (xfr#2256845, to-chk=0/2994364)    
rsync error: some files/attrs were not transferred (see previous errors) (code 23) at main.c(1333) [sender=3.2.3]

Also note the transfer speed: we seem capped at 76MB/s, or 608Mbit/s. This is not as fast as I was expecting: the USB connection seems to be at around 5Gbps:

anarcat@curie:~$ lsusb -tv   head -4
/:  Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/6p, 5000M
    ID 1d6b:0003 Linux Foundation 3.0 root hub
     __ Port 1: Dev 4, If 0, Class=Mass Storage, Driver=uas, 5000M
        ID 0b05:1932 ASUSTek Computer, Inc.

So it shouldn't cap at that speed. It's possible the USB adapter is failing to give me the full speed though. It's not the M.2 SSD drive either, as that has a ~500MB/s bandwidth, acccording to its spec. At this point, we're about ready to do the final configuration. We drop to single user mode and do the rest of the procedure. That used to be shutdown now, but it seems like the systemd switch broke that, so now you can reboot into grub and pick the "recovery" option. Alternatively, you might try systemctl rescue, as I found out. I also wanted to copy the drive over to another new NVMe drive, but that failed: it looks like the USB controller I have doesn't work with older, non-NVME drives.

Boot configuration Now we need to enter the new system to rebuild the boot loader and initrd and so on. First, we bind mounts and chroot into the ZFS disk:

mount --rbind /dev  /mnt/dev &&
mount --rbind /proc /mnt/proc &&
mount --rbind /sys  /mnt/sys &&
chroot /mnt /bin/bash

Next we add an extra service that imports the bpool on boot, to make sure it survives a zpool.cache destruction:

cat > /etc/systemd/system/zfs-import-bpool.service <<EOF
[Unit]
DefaultDependencies=no
Before=zfs-import-scan.service
Before=zfs-import-cache.service
[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/sbin/zpool import -N -o cachefile=none bpool
# Work-around to preserve zpool cache:
ExecStartPre=-/bin/mv /etc/zfs/zpool.cache /etc/zfs/preboot_zpool.cache
ExecStartPost=-/bin/mv /etc/zfs/preboot_zpool.cache /etc/zfs/zpool.cache
[Install]
WantedBy=zfs-import.target
EOF

Enable the service:

systemctl enable zfs-import-bpool.service

I had to trim down /etc/fstab and /etc/crypttab to only contain references to the legacy filesystems (/srv is still BTRFS!). If we don't already have a tmpfs defined in /etc/fstab:

ln -s /usr/share/systemd/tmp.mount /etc/systemd/system/ &&
systemctl enable tmp.mount

Rebuild boot loader with support for ZFS, but also to workaround GRUB's missing zpool-features support:

grub-probe /boot   grep -q zfs &&
update-initramfs -c -k all &&
sed -i 's,GRUB_CMDLINE_LINUX.*,GRUB_CMDLINE_LINUX="root=ZFS=rpool/ROOT/debian",' /etc/default/grub &&
update-grub

For good measure, make sure the right disk is configured here, for example you might want to tag both drives in a RAID array:

dpkg-reconfigure grub-pc

Install grub to EFI while you're there:

grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=debian --recheck --no-floppy

Filesystem mount ordering. The rationale here in the OpenZFS guide is a little strange, but I don't dare ignore that.

mkdir /etc/zfs/zfs-list.cache
touch /etc/zfs/zfs-list.cache/bpool
touch /etc/zfs/zfs-list.cache/rpool
zed -F &

Verify that zed updated the cache by making sure these are not empty:

cat /etc/zfs/zfs-list.cache/bpool
cat /etc/zfs/zfs-list.cache/rpool

Once the files have data, stop zed:

fg
Press Ctrl-C.

Fix the paths to eliminate /mnt:

sed -Ei "s /mnt/? / " /etc/zfs/zfs-list.cache/*

Snapshot initial install:

zfs snapshot bpool/BOOT/debian@install
zfs snapshot rpool/ROOT/debian@install

Exit chroot:

exit

Finalizing One last sync was done in rescue mode:

for fs in /boot/ /boot/efi/ / /home/; do
    echo "syncing $fs to /mnt$fs..." && 
    rsync -aSHAXx --info=progress2 --delete $fs /mnt$fs
done

Then we unmount all filesystems:

mount   grep -v zfs   tac   awk '/\/mnt/  print $3 '   xargs -i  umount -lf  
zpool export -a

Reboot, swap the drives, and boot in ZFS. Hurray!

Benchmarks This is a test that was ran in single-user mode using fio and the Ars Technica recommended tests, which are:

• Single 4KiB random write process:

   fio --name=randwrite4k1x --ioengine=posixaio --rw=randwrite --bs=4k --size=4g --numjobs=1 --iodepth=1 --runtime=60 --time_based --end_fsync=1
  

• 16 parallel 64KiB random write processes:

   fio --name=randwrite64k16x --ioengine=posixaio --rw=randwrite --bs=64k --size=256m --numjobs=16 --iodepth=16 --runtime=60 --time_based --end_fsync=1
  

• Single 1MiB random write process:

   fio --name=randwrite1m1x --ioengine=posixaio --rw=randwrite --bs=1m --size=16g --numjobs=1 --iodepth=1 --runtime=60 --time_based --end_fsync=1
  

Strangely, that's not exactly what the author, Jim Salter, did in his actual test bench used in the ZFS benchmarking article. The first thing is there's no read test at all, which is already pretty strange. But also it doesn't include stuff like dropping caches or repeating results. So here's my variation, which i called fio-ars-bench.sh for now. It just batches a bunch of fio tests, one by one, 60 seconds each. It should take about 12 minutes to run, as there are 3 pair of tests, read/write, with and without async. My bias, before building, running and analysing those results is that ZFS should outperform the traditional stack on writes, but possibly not on reads. It's also possible it outperforms it on both, because it's a newer drive. A new test might be possible with a new external USB drive as well, although I doubt I will find the time to do this.

Results All tests were done on WD blue SN550 drives, which claims to be able to push 2400MB/s read and 1750MB/s write. An extra drive was bought to move the LVM setup from a WDC WDS500G1B0B-00AS40 SSD, a WD blue M.2 2280 SSD that was at least 5 years old, spec'd at 560MB/s read, 530MB/s write. Benchmarks were done on the M.2 SSD drive but discarded so that the drive difference is not a factor in the test. In practice, I'm going to assume we'll never reach those numbers because we're not actually NVMe (this is an old workstation!) so the bottleneck isn't the disk itself. For our purposes, it might still give us useful results.

Rescue test, LUKS/LVM/ext4 Those tests were performed with everything shutdown, after either entering the system in rescue mode, or by reaching that target with:

systemctl rescue

The network might have been started before or after the test as well:

systemctl start systemd-networkd

So it should be fairly reliable as basically nothing else is running. Raw numbers, from the ?job-curie-lvm.log, converted to MiB/s and manually merged:

test	read I/O	read IOPS	write I/O	write IOPS
rand4k4g1x	39.27	10052	212.15	54310
rand4k4g1x--fsync=1	39.29	10057	2.73	699
rand64k256m16x	1297.00	20751	1068.57	17097
rand64k256m16x--fsync=1	1290.90	20654	353.82	5661
rand1m16g1x	315.15	315	563.77	563
rand1m16g1x--fsync=1	345.88	345	157.01	157

Peaks are at about 20k IOPS and ~1.3GiB/s read, 1GiB/s write in the 64KB blocks with 16 jobs. Slowest is the random 4k block sync write at an abysmal 3MB/s and 700 IOPS The 1MB read/write tests have lower IOPS, but that is expected.

Rescue test, ZFS This test was also performed in rescue mode. Raw numbers, from the ?job-curie-zfs.log, converted to MiB/s and manually merged:

test	read I/O	read IOPS	write I/O	write IOPS
rand4k4g1x	77.20	19763	27.13	6944
rand4k4g1x--fsync=1	76.16	19495	6.53	1673
rand64k256m16x	1882.40	30118	70.58	1129
rand64k256m16x--fsync=1	1865.13	29842	71.98	1151
rand1m16g1x	921.62	921	102.21	102
rand1m16g1x--fsync=1	908.37	908	64.30	64

Peaks are at 1.8GiB/s read, also in the 64k job like above, but much faster. The write is, as expected, much slower at 70MiB/s (compared to 1GiB/s!), but it should be noted the sync write doesn't degrade performance compared to async writes (although it's still below the LVM 300MB/s).

Conclusions Really, ZFS has trouble performing in all write conditions. The random 4k sync write test is the only place where ZFS outperforms LVM in writes, and barely (7MiB/s vs 3MiB/s). Everywhere else, writes are much slower, sometimes by an order of magnitude. And before some ZFS zealot jumps in talking about the SLOG or some other cache that could be added to improved performance, I'll remind you that those numbers are on a bare bones NVMe drive, pretty much as fast storage as you can find on this machine. Adding another NVMe drive as a cache probably will not improve write performance here. Still, those are very different results than the tests performed by Salter which shows ZFS beating traditional configurations in all categories but uncached 4k reads (not writes!). That said, those tests are very different from the tests I performed here, where I test writes on a single disk, not a RAID array, which might explain the discrepancy. Also, note that neither LVM or ZFS manage to reach the 2400MB/s read and 1750MB/s write performance specification. ZFS does manage to reach 82% of the read performance (1973MB/s) and LVM 64% of the write performance (1120MB/s). LVM hits 57% of the read performance and ZFS hits barely 6% of the write performance. Overall, I'm a bit disappointed in the ZFS write performance here, I must say. Maybe I need to tweak the record size or some other ZFS voodoo, but I'll note that I didn't have to do any such configuration on the other side to kick ZFS in the pants...

Real world experience This section document not synthetic backups, but actual real world workloads, comparing before and after I switched my workstation to ZFS.

Docker performance I had the feeling that running some git hook (which was firing a Docker container) was "slower" somehow. It seems that, at runtime, ZFS backends are significant slower than their overlayfs/ext4 equivalent:

May 16 14:42:52 curie systemd[1]: home-docker-overlay2-17e4d24228decc2d2d493efc401dbfb7ac29739da0e46775e122078d9daf3e87\x2dinit-merged.mount: Succeeded.
May 16 14:42:52 curie systemd[5161]: home-docker-overlay2-17e4d24228decc2d2d493efc401dbfb7ac29739da0e46775e122078d9daf3e87\x2dinit-merged.mount: Succeeded.
May 16 14:42:52 curie systemd[1]: home-docker-overlay2-17e4d24228decc2d2d493efc401dbfb7ac29739da0e46775e122078d9daf3e87-merged.mount: Succeeded.
May 16 14:42:53 curie dockerd[1723]: time="2022-05-16T14:42:53.087219426-04:00" level=info msg="starting signal loop" namespace=moby path=/run/docker/containerd/daemon/io.containerd.runtime.v2.task/moby/af22586fba07014a4d10ab19da10cf280db7a43cad804d6c1e9f2682f12b5f10 pid=151170
May 16 14:42:53 curie systemd[1]: Started libcontainer container af22586fba07014a4d10ab19da10cf280db7a43cad804d6c1e9f2682f12b5f10.
May 16 14:42:54 curie systemd[1]: docker-af22586fba07014a4d10ab19da10cf280db7a43cad804d6c1e9f2682f12b5f10.scope: Succeeded.
May 16 14:42:54 curie dockerd[1723]: time="2022-05-16T14:42:54.047297800-04:00" level=info msg="shim disconnected" id=af22586fba07014a4d10ab19da10cf280db7a43cad804d6c1e9f2682f12b5f10
May 16 14:42:54 curie dockerd[998]: time="2022-05-16T14:42:54.051365015-04:00" level=info msg="ignoring event" container=af22586fba07014a4d10ab19da10cf280db7a43cad804d6c1e9f2682f12b5f10 module=libcontainerd namespace=moby topic=/tasks/delete type="*events.TaskDelete"
May 16 14:42:54 curie systemd[2444]: run-docker-netns-f5453c87c879.mount: Succeeded.
May 16 14:42:54 curie systemd[5161]: run-docker-netns-f5453c87c879.mount: Succeeded.
May 16 14:42:54 curie systemd[2444]: home-docker-overlay2-17e4d24228decc2d2d493efc401dbfb7ac29739da0e46775e122078d9daf3e87-merged.mount: Succeeded.
May 16 14:42:54 curie systemd[5161]: home-docker-overlay2-17e4d24228decc2d2d493efc401dbfb7ac29739da0e46775e122078d9daf3e87-merged.mount: Succeeded.
May 16 14:42:54 curie systemd[1]: run-docker-netns-f5453c87c879.mount: Succeeded.
May 16 14:42:54 curie systemd[1]: home-docker-overlay2-17e4d24228decc2d2d493efc401dbfb7ac29739da0e46775e122078d9daf3e87-merged.mount: Succeeded.

Translating this:

• container setup: ~1 second
• container runtime: ~1 second
• container teardown: ~1 second
• total runtime: 2-3 seconds

Obviously, those timestamps are not quite accurate enough to make precise measurements... After I switched to ZFS:

mai 30 15:31:39 curie systemd[1]: var-lib-docker-zfs-graph-41ce08fb7a1d3a9c101694b82722f5621c0b4819bd1d9f070933fd1e00543cdf\x2dinit.mount: Succeeded. 
mai 30 15:31:39 curie systemd[5287]: var-lib-docker-zfs-graph-41ce08fb7a1d3a9c101694b82722f5621c0b4819bd1d9f070933fd1e00543cdf\x2dinit.mount: Succeeded. 
mai 30 15:31:40 curie systemd[1]: var-lib-docker-zfs-graph-41ce08fb7a1d3a9c101694b82722f5621c0b4819bd1d9f070933fd1e00543cdf.mount: Succeeded. 
mai 30 15:31:40 curie systemd[5287]: var-lib-docker-zfs-graph-41ce08fb7a1d3a9c101694b82722f5621c0b4819bd1d9f070933fd1e00543cdf.mount: Succeeded. 
mai 30 15:31:41 curie dockerd[3199]: time="2022-05-30T15:31:41.551403693-04:00" level=info msg="starting signal loop" namespace=moby path=/run/docker/containerd/daemon/io.containerd.runtime.v2.task/moby/42a1a1ed5912a7227148e997f442e7ab2e5cc3558aa3471548223c5888c9b142 pid=141080 
mai 30 15:31:41 curie systemd[1]: run-docker-runtime\x2drunc-moby-42a1a1ed5912a7227148e997f442e7ab2e5cc3558aa3471548223c5888c9b142-runc.ZVcjvl.mount: Succeeded. 
mai 30 15:31:41 curie systemd[5287]: run-docker-runtime\x2drunc-moby-42a1a1ed5912a7227148e997f442e7ab2e5cc3558aa3471548223c5888c9b142-runc.ZVcjvl.mount: Succeeded. 
mai 30 15:31:41 curie systemd[1]: Started libcontainer container 42a1a1ed5912a7227148e997f442e7ab2e5cc3558aa3471548223c5888c9b142. 
mai 30 15:31:45 curie systemd[1]: docker-42a1a1ed5912a7227148e997f442e7ab2e5cc3558aa3471548223c5888c9b142.scope: Succeeded. 
mai 30 15:31:45 curie dockerd[3199]: time="2022-05-30T15:31:45.883019128-04:00" level=info msg="shim disconnected" id=42a1a1ed5912a7227148e997f442e7ab2e5cc3558aa3471548223c5888c9b142 
mai 30 15:31:45 curie dockerd[1726]: time="2022-05-30T15:31:45.883064491-04:00" level=info msg="ignoring event" container=42a1a1ed5912a7227148e997f442e7ab2e5cc3558aa3471548223c5888c9b142 module=libcontainerd namespace=moby topic=/tasks/delete type="*events.TaskDelete" 
mai 30 15:31:45 curie systemd[1]: run-docker-netns-e45f5cf5f465.mount: Succeeded. 
mai 30 15:31:45 curie systemd[5287]: run-docker-netns-e45f5cf5f465.mount: Succeeded. 
mai 30 15:31:45 curie systemd[1]: var-lib-docker-zfs-graph-41ce08fb7a1d3a9c101694b82722f5621c0b4819bd1d9f070933fd1e00543cdf.mount: Succeeded. 
mai 30 15:31:45 curie systemd[5287]: var-lib-docker-zfs-graph-41ce08fb7a1d3a9c101694b82722f5621c0b4819bd1d9f070933fd1e00543cdf.mount: Succeeded.

That's double or triple the run time, from 2 seconds to 6 seconds. Most of the time is spent in run time, inside the container. Here's the breakdown:

• container setup: ~2 seconds
• container run: ~4 seconds
• container teardown: ~1 second
• total run time: about ~6-7 seconds

That's a two- to three-fold increase! Clearly something is going on here that I should tweak. It's possible that code path is less optimized in Docker. I also worry about podman, but apparently it also supports ZFS backends. Possibly it would perform better, but at this stage I wouldn't have a good comparison: maybe it would have performed better on non-ZFS as well...

Interactivity While doing the offsite backups (below), the system became somewhat "sluggish". I felt everything was slow, and I estimate it introduced ~50ms latency in any input device. Arguably, those are all USB and the external drive was connected through USB, but I suspect the ZFS drivers are not as well tuned with the scheduler as the regular filesystem drivers...

Recovery procedures For test purposes, I unmounted all systems during the procedure:

umount /mnt/boot/efi /mnt/boot/run
umount -a -t zfs
zpool export -a

And disconnected the drive, to see how I would recover this system from another Linux system in case of a total motherboard failure. To import an existing pool, plug the device, then import the pool with an alternate root, so it doesn't mount over your existing filesystems, then you mount the root filesystem and all the others:

zpool import -l -a -R /mnt &&
zfs mount rpool/ROOT/debian &&
zfs mount -a &&
mount /dev/sdc2 /mnt/boot/efi &&
mount -t tmpfs tmpfs /mnt/run &&
mkdir /mnt/run/lock

Offsite backup Part of the goal of using ZFS is to simplify and harden backups. I wanted to experiment with shorter recovery times specifically both point in time recovery objective and recovery time objective and faster incremental backups. This is, therefore, part of my backup services. This section documents how an external NVMe enclosure was setup in a pool to mirror the datasets from my workstation. The final setup should include syncoid copying datasets to the backup server regularly, but I haven't finished that configuration yet.

Partitioning The above partitioning procedure used sgdisk, but I couldn't figure out how to do this with sgdisk, so this uses sfdisk to dump the partition from the first disk to an external, identical drive:

sfdisk -d /dev/nvme0n1   sfdisk --no-reread /dev/sda --force

Pool creation This is similar to the main pool creation, except we tweaked a few bits after changing the upstream procedure:

zpool create \
        -o cachefile=/etc/zfs/zpool.cache \
        -o ashift=12 -d \
        -o feature@async_destroy=enabled \
        -o feature@bookmarks=enabled \
        -o feature@embedded_data=enabled \
        -o feature@empty_bpobj=enabled \
        -o feature@enabled_txg=enabled \
        -o feature@extensible_dataset=enabled \
        -o feature@filesystem_limits=enabled \
        -o feature@hole_birth=enabled \
        -o feature@large_blocks=enabled \
        -o feature@lz4_compress=enabled \
        -o feature@spacemap_histogram=enabled \
        -o feature@zpool_checkpoint=enabled \
        -O acltype=posixacl -O xattr=sa \
        -O compression=lz4 \
        -O devices=off \
        -O relatime=on \
        -O canmount=off \
        -O mountpoint=/boot -R /mnt \
        bpool-tubman /dev/sdb3

The change from the main boot pool are:

• no unicode normalization
• different device path (sdb used to be the M.2 device, it's now nvme0n1)
• reordered parameters

Main pool creation is:

zpool create \
        -o ashift=12 \
        -O encryption=on -O keylocation=prompt -O keyformat=passphrase \
        -O acltype=posixacl -O xattr=sa -O dnodesize=auto \
        -O compression=zstd \
        -O relatime=on \
        -O canmount=off \
        -O mountpoint=/ -R /mnt \
        rpool-tubman /dev/sdb4

First sync I used syncoid to copy all pools over to the external device. syncoid is a thing that's part of the sanoid project which is specifically designed to sync snapshots between pool, typically over SSH links but it can also operate locally. The sanoid command had a --readonly argument to simulate changes, but syncoid didn't so I tried to fix that with an upstream PR. It seems it would be better to do this by hand, but this was much easier. The full first sync was:

root@curie:/home/anarcat# ./bin/syncoid -r  bpool bpool-tubman
CRITICAL ERROR: Target bpool-tubman exists but has no snapshots matching with bpool!
                Replication to target would require destroying existing
                target. Cowardly refusing to destroy your existing target.
          NOTE: Target bpool-tubman dataset is < 64MB used - did you mistakenly run
                 zfs create bpool-tubman  on the target? ZFS initial
                replication must be to a NON EXISTENT DATASET, which will
                then be CREATED BY the initial replication process.
INFO: Sending oldest full snapshot bpool/BOOT@test (~ 42 KB) to new target filesystem:
44.2KiB 0:00:00 [4.19MiB/s] [========================================================================================================================] 103%            
INFO: Updating new target filesystem with incremental bpool/BOOT@test ... syncoid_curie_2022-05-30:12:50:39 (~ 4 KB):
2.13KiB 0:00:00 [ 114KiB/s] [===============================================================>                                                         ] 53%            
INFO: Sending oldest full snapshot bpool/BOOT/debian@install (~ 126.0 MB) to new target filesystem:
 126MiB 0:00:00 [ 308MiB/s] [=======================================================================================================================>] 100%            
INFO: Updating new target filesystem with incremental bpool/BOOT/debian@install ... syncoid_curie_2022-05-30:12:50:39 (~ 113.4 MB):
 113MiB 0:00:00 [ 315MiB/s] [=======================================================================================================================>] 100%
root@curie:/home/anarcat# ./bin/syncoid -r  rpool rpool-tubman
CRITICAL ERROR: Target rpool-tubman exists but has no snapshots matching with rpool!
                Replication to target would require destroying existing
                target. Cowardly refusing to destroy your existing target.
          NOTE: Target rpool-tubman dataset is < 64MB used - did you mistakenly run
                 zfs create rpool-tubman  on the target? ZFS initial
                replication must be to a NON EXISTENT DATASET, which will
                then be CREATED BY the initial replication process.
INFO: Sending oldest full snapshot rpool/ROOT@syncoid_curie_2022-05-30:12:50:51 (~ 69 KB) to new target filesystem:
44.2KiB 0:00:00 [2.44MiB/s] [===========================================================================>                                             ] 63%            
INFO: Sending oldest full snapshot rpool/ROOT/debian@install (~ 25.9 GB) to new target filesystem:
25.9GiB 0:03:33 [ 124MiB/s] [=======================================================================================================================>] 100%            
INFO: Updating new target filesystem with incremental rpool/ROOT/debian@install ... syncoid_curie_2022-05-30:12:50:52 (~ 3.9 GB):
3.92GiB 0:00:33 [ 119MiB/s] [======================================================================================================================>  ] 99%            
INFO: Sending oldest full snapshot rpool/home@syncoid_curie_2022-05-30:12:55:04 (~ 276.8 GB) to new target filesystem:
 277GiB 0:27:13 [ 174MiB/s] [=======================================================================================================================>] 100%            
INFO: Sending oldest full snapshot rpool/home/root@syncoid_curie_2022-05-30:13:22:19 (~ 2.2 GB) to new target filesystem:
2.22GiB 0:00:25 [90.2MiB/s] [=======================================================================================================================>] 100%            
INFO: Sending oldest full snapshot rpool/var@syncoid_curie_2022-05-30:13:22:47 (~ 5.6 GB) to new target filesystem:
5.56GiB 0:00:32 [ 176MiB/s] [=======================================================================================================================>] 100%            
INFO: Sending oldest full snapshot rpool/var/cache@syncoid_curie_2022-05-30:13:23:22 (~ 627.3 MB) to new target filesystem:
 627MiB 0:00:03 [ 169MiB/s] [=======================================================================================================================>] 100%            
INFO: Sending oldest full snapshot rpool/var/lib@syncoid_curie_2022-05-30:13:23:28 (~ 69 KB) to new target filesystem:
44.2KiB 0:00:00 [1.40MiB/s] [===========================================================================>                                             ] 63%            
INFO: Sending oldest full snapshot rpool/var/lib/docker@syncoid_curie_2022-05-30:13:23:28 (~ 442.6 MB) to new target filesystem:
 443MiB 0:00:04 [ 103MiB/s] [=======================================================================================================================>] 100%            
INFO: Sending oldest full snapshot rpool/var/lib/docker/05c0de7fabbea60500eaa495d0d82038249f6faa63b12914737c4d71520e62c5@266253254 (~ 6.3 MB) to new target filesystem:
6.49MiB 0:00:00 [12.9MiB/s] [========================================================================================================================] 102%            
INFO: Updating new target filesystem with incremental rpool/var/lib/docker/05c0de7fabbea60500eaa495d0d82038249f6faa63b12914737c4d71520e62c5@266253254 ... syncoid_curie_2022-05-30:13:23:34 (~ 4 KB):
1.52KiB 0:00:00 [27.6KiB/s] [============================================>                                                                            ] 38%            
INFO: Sending oldest full snapshot rpool/var/lib/flatpak@syncoid_curie_2022-05-30:13:23:36 (~ 2.0 GB) to new target filesystem:
2.00GiB 0:00:17 [ 115MiB/s] [=======================================================================================================================>] 100%            
INFO: Sending oldest full snapshot rpool/var/tmp@syncoid_curie_2022-05-30:13:23:55 (~ 57.0 MB) to new target filesystem:
61.8MiB 0:00:01 [45.0MiB/s] [========================================================================================================================] 108%            
INFO: Clone is recreated on target rpool-tubman/var/lib/docker/ed71ddd563a779ba6fb37b3b1d0cc2c11eca9b594e77b4b234867ebcb162b205 based on rpool/var/lib/docker/05c0de7fabbea60500eaa495d0d82038249f6faa63b12914737c4d71520e62c5@266253254
INFO: Sending oldest full snapshot rpool/var/lib/docker/ed71ddd563a779ba6fb37b3b1d0cc2c11eca9b594e77b4b234867ebcb162b205@syncoid_curie_2022-05-30:13:23:58 (~ 218.6 MB) to new target filesystem:
 219MiB 0:00:01 [ 151MiB/s] [=======================================================================================================================>] 100%

Funny how the CRITICAL ERROR doesn't actually stop syncoid and it just carries on merrily doing when it's telling you it's "cowardly refusing to destroy your existing target"... Maybe that's because my pull request broke something though... During the transfer, the computer was very sluggish: everything feels like it has ~30-50ms latency extra:

anarcat@curie:sanoid$ LANG=C top -b  -n 1   head -20
top - 13:07:05 up 6 days,  4:01,  1 user,  load average: 16.13, 16.55, 11.83
Tasks: 606 total,   6 running, 598 sleeping,   0 stopped,   2 zombie
%Cpu(s): 18.8 us, 72.5 sy,  1.2 ni,  5.0 id,  1.2 wa,  0.0 hi,  1.2 si,  0.0 st
MiB Mem :  15898.4 total,   1387.6 free,  13170.0 used,   1340.8 buff/cache
MiB Swap:      0.0 total,      0.0 free,      0.0 used.   1319.8 avail Mem 
    PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND
     70 root      20   0       0      0      0 S  83.3   0.0   6:12.67 kswapd0
4024878 root      20   0  282644  96432  10288 S  44.4   0.6   0:11.43 puppet
3896136 root      20   0   35328  16528     48 S  22.2   0.1   2:08.04 mbuffer
3896135 root      20   0   10328    776    168 R  16.7   0.0   1:22.93 zfs
3896138 root      20   0   10588    788    156 R  16.7   0.0   1:49.30 zfs
    350 root       0 -20       0      0      0 R  11.1   0.0   1:03.53 z_rd_int
    351 root       0 -20       0      0      0 S  11.1   0.0   1:04.15 z_rd_int
3896137 root      20   0    4384    352    244 R  11.1   0.0   0:44.73 pv
4034094 anarcat   30  10   20028  13960   2428 S  11.1   0.1   0:00.70 mbsync
4036539 anarcat   20   0    9604   3464   2408 R  11.1   0.0   0:00.04 top
    352 root       0 -20       0      0      0 S   5.6   0.0   1:03.64 z_rd_int
    353 root       0 -20       0      0      0 S   5.6   0.0   1:03.64 z_rd_int
    354 root       0 -20       0      0      0 S   5.6   0.0   1:04.01 z_rd_int

I wonder how much of that is due to syncoid, particularly because I often saw mbuffer and pv in there which are not strictly necessary to do those kind of operations, as far as I understand. Once that's done, export the pools to disconnect the drive:

zpool export bpool-tubman
zpool export rpool-tubman

Raw disk benchmark Copied the 512GB SSD/M.2 device to another 1024GB NVMe/M.2 device:

anarcat@curie:~$ sudo dd if=/dev/sdb of=/dev/sdc bs=4M status=progress conv=fdatasync
499944259584 octets (500 GB, 466 GiB) copi s, 1713 s, 292 MB/s
119235+1 enregistrements lus
119235+1 enregistrements  crits
500107862016 octets (500 GB, 466 GiB) copi s, 1719,93 s, 291 MB/s

... while both over USB, whoohoo 300MB/s!

Monitoring ZFS should be monitoring your pools regularly. Normally, the [[!debman zed]] daemon monitors all ZFS events. It is the thing that will report when a scrub failed, for example. See this configuration guide. Scrubs should be regularly scheduled to ensure consistency of the pool. This can be done in newer zfsutils-linux versions (bullseye-backports or bookworm) with one of those, depending on the desired frequency:

systemctl enable zfs-scrub-weekly@rpool.timer --now
systemctl enable zfs-scrub-monthly@rpool.timer --now

When the scrub runs, if it finds anything it will send an event which will get picked up by the zed daemon which will then send a notification, see below for an example. TODO: deploy on curie, if possible (probably not because no RAID) TODO: this should be in Puppet

Scrub warning example So what happens when problems are found? Here's an example of how I dealt with an error I received. After setting up another server (tubman) with ZFS, I eventually ended up getting a warning from the ZFS toolchain.

Date: Sun, 09 Oct 2022 00:58:08 -0400
From: root <root@anarc.at>
To: root@anarc.at
Subject: ZFS scrub_finish event for rpool on tubman
ZFS has finished a scrub:
   eid: 39536
 class: scrub_finish
  host: tubman
  time: 2022-10-09 00:58:07-0400
  pool: rpool
 state: ONLINE
status: One or more devices has experienced an unrecoverable error.  An
        attempt was made to correct the error.  Applications are unaffected.
action: Determine if the device needs to be replaced, and clear the errors
        using 'zpool clear' or replace the device with 'zpool replace'.
   see: https://openzfs.github.io/openzfs-docs/msg/ZFS-8000-9P
  scan: scrub repaired 0B in 00:33:57 with 0 errors on Sun Oct  9 00:58:07 2022
config:
        NAME        STATE     READ WRITE CKSUM
        rpool       ONLINE       0     0     0
          mirror-0  ONLINE       0     0     0
            sdb4    ONLINE       0     1     0
            sdc4    ONLINE       0     0     0
        cache
          sda3      ONLINE       0     0     0
errors: No known data errors

This, in itself, is a little worrisome. But it helpfully links to this more detailed documentation (and props up there: the link still works) which explains this is a "minor" problem (something that could be included in the report). In this case, this happened on a server setup on 2021-04-28, but the disks and server hardware are much older. The server itself (marcos v1) was built around 2011, over 10 years ago now. The hard drive in question is:

root@tubman:~# smartctl -i -qnoserial /dev/sdb
smartctl 7.2 2020-12-30 r5155 [x86_64-linux-5.10.0-15-amd64] (local build)
Copyright (C) 2002-20, Bruce Allen, Christian Franke, www.smartmontools.org
=== START OF INFORMATION SECTION ===
Model Family:     Seagate BarraCuda 3.5
Device Model:     ST4000DM004-2CV104
Firmware Version: 0001
User Capacity:    4,000,787,030,016 bytes [4.00 TB]
Sector Sizes:     512 bytes logical, 4096 bytes physical
Rotation Rate:    5425 rpm
Form Factor:      3.5 inches
Device is:        In smartctl database [for details use: -P show]
ATA Version is:   ACS-3 T13/2161-D revision 5
SATA Version is:  SATA 3.1, 6.0 Gb/s (current: 3.0 Gb/s)
Local Time is:    Tue Oct 11 11:02:32 2022 EDT
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

Some more SMART stats:

root@tubman:~# smartctl -a -qnoserial /dev/sdb   grep -e  Head_Flying_Hours -e Power_On_Hours -e Total_LBA -e 'Sector Sizes'
Sector Sizes:     512 bytes logical, 4096 bytes physical
  9 Power_On_Hours          0x0032   086   086   000    Old_age   Always       -       12464 (206 202 0)
240 Head_Flying_Hours       0x0000   100   253   000    Old_age   Offline      -       10966h+55m+23.757s
241 Total_LBAs_Written      0x0000   100   253   000    Old_age   Offline      -       21107792664
242 Total_LBAs_Read         0x0000   100   253   000    Old_age   Offline      -       3201579750

That's over a year of power on, which shouldn't be so bad. It has written about 10TB of data (21107792664 LBAs * 512 byte/LBA), which is about two full writes. According to its specification, this device is supposed to support 55 TB/year of writes, so we're far below spec. Note that are still far from the "non-recoverable read error per bits" spec (1 per 10E15), as we've basically read 13E12 bits (3201579750 LBAs * 512 byte/LBA = 13E12 bits). It's likely this disk was made in 2018, so it is in its fourth year. Interestingly, /dev/sdc is also a Seagate drive, but of a different series:

root@tubman:~# smartctl -qnoserial  -i /dev/sdb
smartctl 7.2 2020-12-30 r5155 [x86_64-linux-5.10.0-15-amd64] (local build)
Copyright (C) 2002-20, Bruce Allen, Christian Franke, www.smartmontools.org
=== START OF INFORMATION SECTION ===
Model Family:     Seagate BarraCuda 3.5
Device Model:     ST4000DM004-2CV104
Firmware Version: 0001
User Capacity:    4,000,787,030,016 bytes [4.00 TB]
Sector Sizes:     512 bytes logical, 4096 bytes physical
Rotation Rate:    5425 rpm
Form Factor:      3.5 inches
Device is:        In smartctl database [for details use: -P show]
ATA Version is:   ACS-3 T13/2161-D revision 5
SATA Version is:  SATA 3.1, 6.0 Gb/s (current: 3.0 Gb/s)
Local Time is:    Tue Oct 11 11:21:35 2022 EDT
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

It has seen much more reads than the other disk which is also interesting:

root@tubman:~# smartctl -a -qnoserial /dev/sdc   grep -e  Head_Flying_Hours -e Power_On_Hours -e Total_LBA -e 'Sector Sizes'
Sector Sizes:     512 bytes logical, 4096 bytes physical
  9 Power_On_Hours          0x0032   059   059   000    Old_age   Always       -       36240
240 Head_Flying_Hours       0x0000   100   253   000    Old_age   Offline      -       33994h+10m+52.118s
241 Total_LBAs_Written      0x0000   100   253   000    Old_age   Offline      -       30730174438
242 Total_LBAs_Read         0x0000   100   253   000    Old_age   Offline      -       51894566538

That's 4 years of Head_Flying_Hours, and over 4 years (4 years and 48 days) of Power_On_Hours. The copyright date on that drive's specs goes back to 2016, so it's a much older drive. SMART self-test succeeded.

Remaining issues

• TODO: move send/receive backups to offsite host, see also zfs for alternatives to syncoid/sanoid there
• TODO: setup backup cron job (or timer?)
• TODO: swap still not setup on curie, see zfs
• TODO: document this somewhere: bpool and rpool are both pools and datasets. that's pretty confusing, but also very useful because it allows for pool-wide recursive snapshots, which are used for the backup system

fio improvements I really want to improve my experience with fio. Right now, I'm just cargo-culting stuff from other folks and I don't really like it. stressant is a good example of my struggles, in the sense that it doesn't really work that well for disk tests. I would love to have just a single .fio job file that lists multiple jobs to run serially. For example, this file describes the above workload pretty well:

[global]
# cargo-culting Salter
fallocate=none
ioengine=posixaio
runtime=60
time_based=1
end_fsync=1
stonewall=1
group_reporting=1
# no need to drop caches, done by default
# invalidate=1
# Single 4KiB random read/write process
[randread-4k-4g-1x]
rw=randread
bs=4k
size=4g
numjobs=1
iodepth=1
[randwrite-4k-4g-1x]
rw=randwrite
bs=4k
size=4g
numjobs=1
iodepth=1
# 16 parallel 64KiB random read/write processes:
[randread-64k-256m-16x]
rw=randread
bs=64k
size=256m
numjobs=16
iodepth=16
[randwrite-64k-256m-16x]
rw=randwrite
bs=64k
size=256m
numjobs=16
iodepth=16
# Single 1MiB random read/write process
[randread-1m-16g-1x]
rw=randread
bs=1m
size=16g
numjobs=1
iodepth=1
[randwrite-1m-16g-1x]
rw=randwrite
bs=1m
size=16g
numjobs=1
iodepth=1

... except the jobs are actually started in parallel, even though they are stonewall'd, as far as I can tell by the reports. I sent a mail to the fio mailing list for clarification. It looks like the jobs are started in parallel, but actual (correctly) run serially. It seems like this might just be a matter of reporting the right timestamps in the end, although it does feel like starting all the processes (even if not doing any work yet) could skew the results.

Hangs during procedure During the procedure, it happened a few times where any ZFS command would completely hang. It seems that using an external USB drive to sync stuff didn't work so well: sometimes it would reconnect under a different device (from sdc to sdd, for example), and this would greatly confuse ZFS. Here, for example, is sdd reappearing out of the blue:

May 19 11:22:53 curie kernel: [  699.820301] scsi host4: uas
May 19 11:22:53 curie kernel: [  699.820544] usb 2-1: authorized to connect
May 19 11:22:53 curie kernel: [  699.922433] scsi 4:0:0:0: Direct-Access     ROG      ESD-S1C          0    PQ: 0 ANSI: 6
May 19 11:22:53 curie kernel: [  699.923235] sd 4:0:0:0: Attached scsi generic sg2 type 0
May 19 11:22:53 curie kernel: [  699.923676] sd 4:0:0:0: [sdd] 1953525168 512-byte logical blocks: (1.00 TB/932 GiB)
May 19 11:22:53 curie kernel: [  699.923788] sd 4:0:0:0: [sdd] Write Protect is off
May 19 11:22:53 curie kernel: [  699.923949] sd 4:0:0:0: [sdd] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
May 19 11:22:53 curie kernel: [  699.924149] sd 4:0:0:0: [sdd] Optimal transfer size 33553920 bytes
May 19 11:22:53 curie kernel: [  699.961602]  sdd: sdd1 sdd2 sdd3 sdd4
May 19 11:22:53 curie kernel: [  699.996083] sd 4:0:0:0: [sdd] Attached SCSI disk

Next time I run a ZFS command (say zpool list), the command completely hangs (D state) and this comes up in the logs:

May 19 11:34:21 curie kernel: [ 1387.914843] zio pool=bpool vdev=/dev/sdc3 error=5 type=2 offset=71344128 size=4096 flags=184880
May 19 11:34:21 curie kernel: [ 1387.914859] zio pool=bpool vdev=/dev/sdc3 error=5 type=2 offset=205565952 size=4096 flags=184880
May 19 11:34:21 curie kernel: [ 1387.914874] zio pool=bpool vdev=/dev/sdc3 error=5 type=2 offset=272789504 size=4096 flags=184880
May 19 11:34:21 curie kernel: [ 1387.914906] zio pool=bpool vdev=/dev/sdc3 error=5 type=1 offset=270336 size=8192 flags=b08c1
May 19 11:34:21 curie kernel: [ 1387.914932] zio pool=bpool vdev=/dev/sdc3 error=5 type=1 offset=1073225728 size=8192 flags=b08c1
May 19 11:34:21 curie kernel: [ 1387.914948] zio pool=bpool vdev=/dev/sdc3 error=5 type=1 offset=1073487872 size=8192 flags=b08c1
May 19 11:34:21 curie kernel: [ 1387.915165] zio pool=bpool vdev=/dev/sdc3 error=5 type=2 offset=272793600 size=4096 flags=184880
May 19 11:34:21 curie kernel: [ 1387.915183] zio pool=bpool vdev=/dev/sdc3 error=5 type=2 offset=339853312 size=4096 flags=184880
May 19 11:34:21 curie kernel: [ 1387.915648] WARNING: Pool 'bpool' has encountered an uncorrectable I/O failure and has been suspended.
May 19 11:34:21 curie kernel: [ 1387.915648] 
May 19 11:37:25 curie kernel: [ 1571.558614] task:txg_sync        state:D stack:    0 pid:  997 ppid:     2 flags:0x00004000
May 19 11:37:25 curie kernel: [ 1571.558623] Call Trace:
May 19 11:37:25 curie kernel: [ 1571.558640]  __schedule+0x282/0x870
May 19 11:37:25 curie kernel: [ 1571.558650]  schedule+0x46/0xb0
May 19 11:37:25 curie kernel: [ 1571.558670]  schedule_timeout+0x8b/0x140
May 19 11:37:25 curie kernel: [ 1571.558675]  ? __next_timer_interrupt+0x110/0x110
May 19 11:37:25 curie kernel: [ 1571.558678]  io_schedule_timeout+0x4c/0x80
May 19 11:37:25 curie kernel: [ 1571.558689]  __cv_timedwait_common+0x12b/0x160 [spl]
May 19 11:37:25 curie kernel: [ 1571.558694]  ? add_wait_queue_exclusive+0x70/0x70
May 19 11:37:25 curie kernel: [ 1571.558702]  __cv_timedwait_io+0x15/0x20 [spl]
May 19 11:37:25 curie kernel: [ 1571.558816]  zio_wait+0x129/0x2b0 [zfs]
May 19 11:37:25 curie kernel: [ 1571.558929]  dsl_pool_sync+0x461/0x4f0 [zfs]
May 19 11:37:25 curie kernel: [ 1571.559032]  spa_sync+0x575/0xfa0 [zfs]
May 19 11:37:25 curie kernel: [ 1571.559138]  ? spa_txg_history_init_io+0x101/0x110 [zfs]
May 19 11:37:25 curie kernel: [ 1571.559245]  txg_sync_thread+0x2e0/0x4a0 [zfs]
May 19 11:37:25 curie kernel: [ 1571.559354]  ? txg_fini+0x240/0x240 [zfs]
May 19 11:37:25 curie kernel: [ 1571.559366]  thread_generic_wrapper+0x6f/0x80 [spl]
May 19 11:37:25 curie kernel: [ 1571.559376]  ? __thread_exit+0x20/0x20 [spl]
May 19 11:37:25 curie kernel: [ 1571.559379]  kthread+0x11b/0x140
May 19 11:37:25 curie kernel: [ 1571.559382]  ? __kthread_bind_mask+0x60/0x60
May 19 11:37:25 curie kernel: [ 1571.559386]  ret_from_fork+0x22/0x30
May 19 11:37:25 curie kernel: [ 1571.559401] task:zed             state:D stack:    0 pid: 1564 ppid:     1 flags:0x00000000
May 19 11:37:25 curie kernel: [ 1571.559404] Call Trace:
May 19 11:37:25 curie kernel: [ 1571.559409]  __schedule+0x282/0x870
May 19 11:37:25 curie kernel: [ 1571.559412]  ? __kmalloc_node+0x141/0x2b0
May 19 11:37:25 curie kernel: [ 1571.559417]  schedule+0x46/0xb0
May 19 11:37:25 curie kernel: [ 1571.559420]  schedule_preempt_disabled+0xa/0x10
May 19 11:37:25 curie kernel: [ 1571.559424]  __mutex_lock.constprop.0+0x133/0x460
May 19 11:37:25 curie kernel: [ 1571.559435]  ? nvlist_xalloc.part.0+0x68/0xc0 [znvpair]
May 19 11:37:25 curie kernel: [ 1571.559537]  spa_all_configs+0x41/0x120 [zfs]
May 19 11:37:25 curie kernel: [ 1571.559644]  zfs_ioc_pool_configs+0x17/0x70 [zfs]
May 19 11:37:25 curie kernel: [ 1571.559752]  zfsdev_ioctl_common+0x697/0x870 [zfs]
May 19 11:37:25 curie kernel: [ 1571.559758]  ? _copy_from_user+0x28/0x60
May 19 11:37:25 curie kernel: [ 1571.559860]  zfsdev_ioctl+0x53/0xe0 [zfs]
May 19 11:37:25 curie kernel: [ 1571.559866]  __x64_sys_ioctl+0x83/0xb0
May 19 11:37:25 curie kernel: [ 1571.559869]  do_syscall_64+0x33/0x80
May 19 11:37:25 curie kernel: [ 1571.559873]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
May 19 11:37:25 curie kernel: [ 1571.559876] RIP: 0033:0x7fcf0ef32cc7
May 19 11:37:25 curie kernel: [ 1571.559878] RSP: 002b:00007fcf0e181618 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
May 19 11:37:25 curie kernel: [ 1571.559881] RAX: ffffffffffffffda RBX: 000055b212f972a0 RCX: 00007fcf0ef32cc7
May 19 11:37:25 curie kernel: [ 1571.559883] RDX: 00007fcf0e181640 RSI: 0000000000005a04 RDI: 000000000000000b
May 19 11:37:25 curie kernel: [ 1571.559885] RBP: 00007fcf0e184c30 R08: 00007fcf08016810 R09: 00007fcf08000080
May 19 11:37:25 curie kernel: [ 1571.559886] R10: 0000000000080000 R11: 0000000000000246 R12: 000055b212f972a0
May 19 11:37:25 curie kernel: [ 1571.559888] R13: 0000000000000000 R14: 00007fcf0e181640 R15: 0000000000000000
May 19 11:37:25 curie kernel: [ 1571.559980] task:zpool           state:D stack:    0 pid:11815 ppid:  3816 flags:0x00004000
May 19 11:37:25 curie kernel: [ 1571.559983] Call Trace:
May 19 11:37:25 curie kernel: [ 1571.559988]  __schedule+0x282/0x870
May 19 11:37:25 curie kernel: [ 1571.559992]  schedule+0x46/0xb0
May 19 11:37:25 curie kernel: [ 1571.559995]  io_schedule+0x42/0x70
May 19 11:37:25 curie kernel: [ 1571.560004]  cv_wait_common+0xac/0x130 [spl]
May 19 11:37:25 curie kernel: [ 1571.560008]  ? add_wait_queue_exclusive+0x70/0x70
May 19 11:37:25 curie kernel: [ 1571.560118]  txg_wait_synced_impl+0xc9/0x110 [zfs]
May 19 11:37:25 curie kernel: [ 1571.560223]  txg_wait_synced+0xc/0x40 [zfs]
May 19 11:37:25 curie kernel: [ 1571.560325]  spa_export_common+0x4cd/0x590 [zfs]
May 19 11:37:25 curie kernel: [ 1571.560430]  ? zfs_log_history+0x9c/0xf0 [zfs]
May 19 11:37:25 curie kernel: [ 1571.560537]  zfsdev_ioctl_common+0x697/0x870 [zfs]
May 19 11:37:25 curie kernel: [ 1571.560543]  ? _copy_from_user+0x28/0x60
May 19 11:37:25 curie kernel: [ 1571.560644]  zfsdev_ioctl+0x53/0xe0 [zfs]
May 19 11:37:25 curie kernel: [ 1571.560649]  __x64_sys_ioctl+0x83/0xb0
May 19 11:37:25 curie kernel: [ 1571.560653]  do_syscall_64+0x33/0x80
May 19 11:37:25 curie kernel: [ 1571.560656]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
May 19 11:37:25 curie kernel: [ 1571.560659] RIP: 0033:0x7fdc23be2cc7
May 19 11:37:25 curie kernel: [ 1571.560661] RSP: 002b:00007ffc8c792478 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
May 19 11:37:25 curie kernel: [ 1571.560664] RAX: ffffffffffffffda RBX: 000055942ca49e20 RCX: 00007fdc23be2cc7
May 19 11:37:25 curie kernel: [ 1571.560666] RDX: 00007ffc8c792490 RSI: 0000000000005a03 RDI: 0000000000000003
May 19 11:37:25 curie kernel: [ 1571.560667] RBP: 00007ffc8c795e80 R08: 00000000ffffffff R09: 00007ffc8c792310
May 19 11:37:25 curie kernel: [ 1571.560669] R10: 000055942ca49e30 R11: 0000000000000246 R12: 00007ffc8c792490
May 19 11:37:25 curie kernel: [ 1571.560671] R13: 000055942ca49e30 R14: 000055942aed2c20 R15: 00007ffc8c795a40

Here's another example, where you see the USB controller bleeping out and back into existence:

mai 19 11:38:39 curie kernel: usb 2-1: USB disconnect, device number 2
mai 19 11:38:39 curie kernel: sd 4:0:0:0: [sdd] Synchronizing SCSI cache
mai 19 11:38:39 curie kernel: sd 4:0:0:0: [sdd] Synchronize Cache(10) failed: Result: hostbyte=DID_ERROR driverbyte=DRIVER_OK
mai 19 11:39:25 curie kernel: INFO: task zed:1564 blocked for more than 241 seconds.
mai 19 11:39:25 curie kernel:       Tainted: P          IOE     5.10.0-14-amd64 #1 Debian 5.10.113-1
mai 19 11:39:25 curie kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
mai 19 11:39:25 curie kernel: task:zed             state:D stack:    0 pid: 1564 ppid:     1 flags:0x00000000
mai 19 11:39:25 curie kernel: Call Trace:
mai 19 11:39:25 curie kernel:  __schedule+0x282/0x870
mai 19 11:39:25 curie kernel:  ? __kmalloc_node+0x141/0x2b0
mai 19 11:39:25 curie kernel:  schedule+0x46/0xb0
mai 19 11:39:25 curie kernel:  schedule_preempt_disabled+0xa/0x10
mai 19 11:39:25 curie kernel:  __mutex_lock.constprop.0+0x133/0x460
mai 19 11:39:25 curie kernel:  ? nvlist_xalloc.part.0+0x68/0xc0 [znvpair]
mai 19 11:39:25 curie kernel:  spa_all_configs+0x41/0x120 [zfs]
mai 19 11:39:25 curie kernel:  zfs_ioc_pool_configs+0x17/0x70 [zfs]
mai 19 11:39:25 curie kernel:  zfsdev_ioctl_common+0x697/0x870 [zfs]
mai 19 11:39:25 curie kernel:  ? _copy_from_user+0x28/0x60
mai 19 11:39:25 curie kernel:  zfsdev_ioctl+0x53/0xe0 [zfs]
mai 19 11:39:25 curie kernel:  __x64_sys_ioctl+0x83/0xb0
mai 19 11:39:25 curie kernel:  do_syscall_64+0x33/0x80
mai 19 11:39:25 curie kernel:  entry_SYSCALL_64_after_hwframe+0x44/0xa9
mai 19 11:39:25 curie kernel: RIP: 0033:0x7fcf0ef32cc7
mai 19 11:39:25 curie kernel: RSP: 002b:00007fcf0e181618 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
mai 19 11:39:25 curie kernel: RAX: ffffffffffffffda RBX: 000055b212f972a0 RCX: 00007fcf0ef32cc7
mai 19 11:39:25 curie kernel: RDX: 00007fcf0e181640 RSI: 0000000000005a04 RDI: 000000000000000b
mai 19 11:39:25 curie kernel: RBP: 00007fcf0e184c30 R08: 00007fcf08016810 R09: 00007fcf08000080
mai 19 11:39:25 curie kernel: R10: 0000000000080000 R11: 0000000000000246 R12: 000055b212f972a0
mai 19 11:39:25 curie kernel: R13: 0000000000000000 R14: 00007fcf0e181640 R15: 0000000000000000
mai 19 11:39:25 curie kernel: INFO: task zpool:11815 blocked for more than 241 seconds.
mai 19 11:39:25 curie kernel:       Tainted: P          IOE     5.10.0-14-amd64 #1 Debian 5.10.113-1
mai 19 11:39:25 curie kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
mai 19 11:39:25 curie kernel: task:zpool           state:D stack:    0 pid:11815 ppid:  2621 flags:0x00004004
mai 19 11:39:25 curie kernel: Call Trace:
mai 19 11:39:25 curie kernel:  __schedule+0x282/0x870
mai 19 11:39:25 curie kernel:  schedule+0x46/0xb0
mai 19 11:39:25 curie kernel:  io_schedule+0x42/0x70
mai 19 11:39:25 curie kernel:  cv_wait_common+0xac/0x130 [spl]
mai 19 11:39:25 curie kernel:  ? add_wait_queue_exclusive+0x70/0x70
mai 19 11:39:25 curie kernel:  txg_wait_synced_impl+0xc9/0x110 [zfs]
mai 19 11:39:25 curie kernel:  txg_wait_synced+0xc/0x40 [zfs]
mai 19 11:39:25 curie kernel:  spa_export_common+0x4cd/0x590 [zfs]
mai 19 11:39:25 curie kernel:  ? zfs_log_history+0x9c/0xf0 [zfs]
mai 19 11:39:25 curie kernel:  zfsdev_ioctl_common+0x697/0x870 [zfs]
mai 19 11:39:25 curie kernel:  ? _copy_from_user+0x28/0x60
mai 19 11:39:25 curie kernel:  zfsdev_ioctl+0x53/0xe0 [zfs]
mai 19 11:39:25 curie kernel:  __x64_sys_ioctl+0x83/0xb0
mai 19 11:39:25 curie kernel:  do_syscall_64+0x33/0x80
mai 19 11:39:25 curie kernel:  entry_SYSCALL_64_after_hwframe+0x44/0xa9
mai 19 11:39:25 curie kernel: RIP: 0033:0x7fdc23be2cc7
mai 19 11:39:25 curie kernel: RSP: 002b:00007ffc8c792478 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
mai 19 11:39:25 curie kernel: RAX: ffffffffffffffda RBX: 000055942ca49e20 RCX: 00007fdc23be2cc7
mai 19 11:39:25 curie kernel: RDX: 00007ffc8c792490 RSI: 0000000000005a03 RDI: 0000000000000003
mai 19 11:39:25 curie kernel: RBP: 00007ffc8c795e80 R08: 00000000ffffffff R09: 00007ffc8c792310
mai 19 11:39:25 curie kernel: R10: 000055942ca49e30 R11: 0000000000000246 R12: 00007ffc8c792490
mai 19 11:39:25 curie kernel: R13: 000055942ca49e30 R14: 000055942aed2c20 R15: 00007ffc8c795a40

I understand those are rather extreme conditions: I would fully expect the pool to stop working if the underlying drives disappear. What doesn't seem acceptable is that a command would completely hang like this.

References See the zfs documentation for more information about ZFS, and tubman for another installation and migration procedure.

The Guile bindings for GnuTLS has been part of GnuTLS since spring 2007 when Ludovic Court s contributed it after some initial discussion. I have been looking into getting back to do GnuTLS coding, and during a recent GnuTLS meeting one topic was Guile bindings. It seemed like a fairly self-contained project to pick up on. It is interesting to re-read the old thread when this work was included: some of the concerns brought up there now have track record to be evaluated on. My opinion that the cost of introducing a new project per language binding today is smaller than the cost of maintaining language bindings as part of the core project. I believe the cost/benefit ratio has changed during the past 15 years: introducing a new project used to come with a significant cost but this is no longer the case, as tooling and processes for packaging have improved. I have had similar experience with Java, C# and Emacs Lisp bindings for GNU Libidn as well, where maintaining them centralized slow down the pace of updates. Andreas Metzler pointed to a similar conclusion reached by Russ Allbery. There are many ways to separate a project into two projects; just copying the files into a new git repository would have been the simplest and was my original plan. However Ludo mentioned git-filter-branch in an email, and the idea of keeping all git history for some of the relevant files seemed worth pursuing to me. I quickly found git-filter-repo which appears to be the recommend approach, and experimenting with it I found a way to filter out the GnuTLS repo into a small git repository that Guile-GnuTLS could be based on. The commands I used were the following, if you want to reproduce things.

$ git clone https://gitlab.com/gnutls/gnutls.git guile-gnutls
$ cd guile-gnutls/
$ git checkout f5dcbdb46df52458e3756193c2a23bf558a3ecfd
$ git-filter-repo --path guile/ --path m4/guile.m4 --path doc/gnutls-guile.texi --path doc/extract-guile-c-doc.scm --path doc/cha-copying.texi --path doc/fdl-1.3.texi

I debated with myself back and forth whether to include some files that would be named the same in the new repository but would share little to no similar lines, for example configure.ac, Makefile.am not to mention README and NEWS. Initially I thought it would be nice to preserve the history for all lines that went into the new project, but this is a subjective judgement call. What brought me over to a more minimal approach was that the contributor history and attribution would be quite strange for the new repository: Should Guile-GnuTLS attribute the work of the thousands of commits to configure.ac which had nothing to do with Guile? Should the people who wrote that be mentioned as contributor of Guile-GnuTLS? I think not. The next step was to get a reasonable GitLab CI/CD pipeline up, to make sure the project builds on some free GNU/Linux distributions like Trisquel and PureOS as well as the usual non-free distributions like Debian and Fedora to have coverage of dpkg and rpm based distributions. I included builds on Alpine and ArchLinux as well, because they tend to trigger other portability issues. I wish there were GNU Guix docker images available for easy testing on that platform as well. The GitLab CI/CD rules for a project like this are fairly simple. To get things out of the door, I tagged the result as v3.7.9 and published a GitLab release page for Guile-GnuTLS that includes OpenPGP-signed source tarballs manually uploaded built on my laptop. The URLs for these tarballs are not very pleasant to work with, and discovering new releases automatically appears unreliable, but I don t know of a better approach. To finish this project, I have proposed a GnuTLS merge request to remove all Guile-related parts from the GnuTLS core. Doing some GnuTLS-related work again felt nice, it was quite some time ago so thank you for giving me this opportunity. Thoughts or comments? Happy hacking!

The following contributors got their Debian Developer accounts in the last two months:

• Sakirnth Nagarasa (sakirnth)
• Philip Rinn (rinni)
• Arnaud Rebillout (arnaudr)
• Marcos Talau (talau)

The following contributors were added as Debian Maintainers in the last two months:

• Xiao Sheng Wen
• Andrea Pappacoda
• Robin Jarry
• Ben Westover
• Michel Alexandre Salim

Congratulations!

Like each month, have a look at the work funded by Freexian s Debian LTS offering. Debian project funding No any major updates on running projects.
Two 1, 2 projects are in the pipeline now.
Tryton project is in a review phase. Gradle projects is still fighting in work. In July, we put aside 2389 EUR to fund Debian projects. We re looking forward to receive more projects from various Debian teams! Learn more about the rationale behind this initiative in this article. Debian LTS contributors In July, 14 contributors have been paid to work on Debian LTS, their reports are available:

• Abhijith PA did 0.00h (out of 14.00h assigned, thus carrying over 14.00h to the next month).
• Andreas R nnquist did 0.00h (out of 0.00h assigned and 10.50h from previous period, thus carrying over 10.50h to the next month).
• Anton Gladky did 23.00h (out of 25.00h assigned, thus carrying over 2.00h to the next month).
• Ben Hutchings did 3.00h (out of 24.00h assigned, thus carrying over 21.00h to the next month).
• Dominik George did 0.00h (out of 0.00h assigned and 22.17h from previous period, thus carrying over 22.17h to the next month).
• Emilio Pozuelo Monfort did 72.00h (out of 35.75h assigned).
• Enrico Zini did 0.00h (out of 0.00h assigned and 8.00h from previous period, thus carrying over 8.00h to the next month).
• Markus Koschany did 35.75h (out of 35.75h assigned).
• Ola Lundqvist did 8.00h (out of 0.00h assigned and 12.00h from previous period, thus carrying over 4.00h to the next month).
• Roberto C. S nchez did 14.25h (out of 29.25h assigned and 2.75h from previous period, thus carrying over 17.75h to the next month).
• Stefano Rivera did 8.00h (out of 6.25h assigned and 20.75h from previous period, thus carrying over 19.00h to the next month).
• Sylvain Beucler did 3.50h (out of 35.75h assigned, thus carrying over 32.25h to the next month).
• Thorsten Alteholz did 20.00h (out of 35.75h assigned).
• Utkarsh Gupta did not report back about their work so we assume they did nothing (out of 35.75 available hours, thus carrying them over to the next month).

Evolution of the situation In July, we have released 3 DLAs. July was the period, when the Debian Stretch had already ELTS status, but Debian Buster was still in the hands of security team. Many member of LTS used this time to update internal infrastructure, documentation and some internal tickets. Now we are ready to take the next release in our hands: Buster! Thanks to our sponsors Sponsors that joined recently are in bold.

• Platinum sponsors:
  • TOSHIBA (for 83 months)
  • GitHub (for 74 months)
  • Civil Infrastructure Platform (CIP) (for 51 months)
• Gold sponsors:
  • Roche Diagnostics International AG (for 94 months)
  • Linode (for 88 months)
  • Babiel GmbH (for 78 months)
  • Plat Home (for 77 months)
  • University of Oxford (for 33 months)
  • Deveryware (for 20 months)
  • VyOS Inc (for 15 months)
  • EDF SA (for 4 months)
• Silver sponsors:
  • Domeneshop AS (for 99 months)
  • The Positive Internet Company (for 99 months)
  • Nantes M tropole (for 93 months)
  • Universit Jean Monnet de St Etienne (for 85 months)
  • Univention GmbH (for 84 months)
  • Ribbon Communications, Inc. (for 78 months)
  • Exonet B.V. (for 68 months)
  • Leibniz Rechenzentrum (for 62 months)
  • CINECA (for 52 months)
  • Minist re de l Europe et des Affaires trang res (for 46 months)
  • Cloudways Ltd (for 35 months)
  • Dinahosting SL (for 33 months)
  • Bauer Xcel Media Deutschland KG (for 27 months)
  • Platform.sh (for 27 months)
  • Moxa Intelligence Co., Ltd. (for 21 months)
  • sipgate GmbH (for 18 months)
  • Tilburg University (for 17 months)
  • OVH US LLC (for 16 months)
  • GSI Helmholtzzentrum f r Schwerionenforschung GmbH (for 8 months)
  • Soliton Systems K.K. (for 5 months)
• Bronze sponsors:
  • Evolix (for 99 months)
  • Seznam.cz, a.s. (for 99 months)
  • Intevation GmbH (for 96 months)
  • Linuxhotel GmbH (for 96 months)
  • Daevel SARL (for 95 months)
  • Bitfolk LTD (for 93 months)
  • Greenbone Networks GmbH (for 93 months)
  • Megaspace Internet Services GmbH (for 93 months)
  • NUMLOG (for 93 months)
  • WinGo AG (for 92 months)
  • Ecole Centrale de Nantes LHEEA (for 88 months)
  • Entr ouvert (for 83 months)
  • Adfinis AG (for 81 months)
  • GNI MEDIA (for 75 months)
  • Laboratoire LEGI UMR 5519 / CNRS (for 75 months)
  • Tesorion (for 75 months)
  • Bearstech (for 67 months)
  • LiHAS (for 67 months)
  • Catalyst IT Ltd (for 61 months)
  • Supagro (for 57 months)
  • Demarcq SAS (for 55 months)
  • Universit Grenoble Alpes (for 41 months)
  • TouchWeb SAS (for 33 months)
  • SPiN AG (for 30 months)
  • CoreFiling (for 26 months)
  • Institut des sciences cognitives Marc Jeannerod (for 20 months)
  • Observatoire des Sciences de l Univers de Grenoble (for 17 months)
  • Tem Innovations GmbH (for 12 months)
  • WordFinder.pro (for 11 months)
  • CNRS DT INSU R sif (for 10 months)
  • Alter Way (for 3 months)

Like each month, have a look at the work funded by Freexian s Debian LTS offering. Debian project funding No any major updates on running projects.
Two 1, 2 projects are in the pipeline now.
Tryton project is in a review phase. Gradle projects is still fighting in work. In June, we put aside 2254 EUR to fund Debian projects. We re looking forward to receive more projects from various Debian teams! Learn more about the rationale behind this initiative in this article. Debian LTS contributors In June, 15 contributors have been paid to work on Debian LTS, their reports are available:

• Abhijith PA did 14.00h (out of 14.00h assigned).
• Andreas R nnquist did 14.50h (out of 14.50h assigned and 10.50h from previous period, thus carrying over 10.50h to the next month).
• Anton Gladky did 16.00h (out of 16.00h assigned).
• Ben Hutchings did 16.00h (out of 0.00h assigned and 16.00h from previous period).
• Chris Lamb did 18.00h (out of 18.00h assigned).
• Dominik George did 1.83h (out of 6.00h assigned and 18.00h from previous period, thus carrying over 22.17h to the next month).
• Emilio Pozuelo Monfort did 30.25h (out of 9.25h assigned and 21.00h from previous period).
• Enrico Zini did 8.00h (out of 9.50h assigned and 6.50h from previous period, thus carrying over 8.00h to the next month).
• Markus Koschany did 30.25h (out of 30.25h assigned).
• Ola Lundqvist did nothing (out of 12.00 available hours, thus carrying them over to the next month).
• Roberto C. S nchez did 27.50h (out of 11.75h assigned and 18.50h from previous period, thus carrying over 2.75h to the next month).
• Stefano Rivera did 8.00h (out of 30.25h assigned, thus carrying over 20.75h to the next month).
• Sylvain Beucler did 30.25h (out of 13.75h assigned and 16.50h from previous period).
• Thorsten Alteholz did 30.25h (out of 30.25h assigned).
• Utkarsh Gupta did not report back about their work so we assume they did nothing (out of 30.25 available hours, thus carrying them over to the next month).

Evolution of the situation In June we released 27 DLAs.

This is a special month, where we have two releases (stretch and jessie) as ELTS and NO release as LTS. Buster is still handled by the security team and will probably be given in LTS hands at the beginning of the August. During this month we are updating the infrastructure, documentation and improve our internal processes to switch to a new release.
Many developers have just returned back from Debconf22, hold in Prizren, Kosovo! Many (E)LTS members could meet face-to-face and discuss some technical and social topics! Also LTS BoF took place, where the project was introduced (link to video).

Thanks to our sponsors Sponsors that joined recently are in bold. We are pleased to welcome Alter Way where their support of Debian is publicly acknowledged at the higher level, see this French quote of Alterway s CEO.

• Platinum sponsors:
  • TOSHIBA (for 82 months)
  • GitHub (for 73 months)
  • Civil Infrastructure Platform (CIP) (for 50 months)
• Gold sponsors:
  • Roche Diagnostics International AG (for 93 months)
  • Linode (for 87 months)
  • Babiel GmbH (for 76 months)
  • Plat Home (for 76 months)
  • University of Oxford (for 32 months)
  • Deveryware (for 19 months)
  • VyOS Inc (for 14 months)
  • EDF SA (for 3 months)
• Silver sponsors:
  • Domeneshop AS (for 98 months)
  • The Positive Internet Company (for 98 months)
  • Nantes M tropole (for 92 months)
  • Univention GmbH (for 83 months)
  • Universit Jean Monnet de St Etienne (for 83 months)
  • Ribbon Communications, Inc. (for 77 months)
  • Exonet B.V. (for 67 months)
  • Leibniz Rechenzentrum (for 61 months)
  • CINECA (for 50 months)
  • Minist re de l Europe et des Affaires trang res (for 45 months)
  • Cloudways Ltd (for 34 months)
  • Dinahosting SL (for 32 months)
  • Bauer Xcel Media Deutschland KG (for 26 months)
  • Platform.sh (for 26 months)
  • Moxa Intelligence Co., Ltd. (for 20 months)
  • sipgate GmbH (for 17 months)
  • Tilburg University (for 16 months)
  • OVH US LLC (for 15 months)
  • GSI Helmholtzzentrum f r Schwerionenforschung GmbH (for 7 months)
  • Soliton Systems K.K. (for 4 months)
• Bronze sponsors:
  • Evolix (for 98 months)
  • Seznam.cz, a.s. (for 98 months)
  • Intevation GmbH (for 95 months)
  • Linuxhotel GmbH (for 95 months)
  • Daevel SARL (for 94 months)
  • Bitfolk LTD (for 92 months)
  • Megaspace Internet Services GmbH (for 92 months)
  • NUMLOG (for 92 months)
  • Greenbone Networks GmbH (for 91 months)
  • WinGo AG (for 91 months)
  • Ecole Centrale de Nantes LHEEA (for 87 months)
  • Entr ouvert (for 82 months)
  • Adfinis AG (for 80 months)
  • GNI MEDIA (for 74 months)
  • Laboratoire LEGI UMR 5519 / CNRS (for 74 months)
  • Tesorion (for 74 months)
  • Bearstech (for 66 months)
  • LiHAS (for 65 months)
  • Catalyst IT Ltd (for 60 months)
  • Supagro (for 55 months)
  • Demarcq SAS (for 54 months)
  • Universit Grenoble Alpes (for 40 months)
  • TouchWeb SAS (for 32 months)
  • SPiN AG (for 29 months)
  • CoreFiling (for 24 months)
  • Institut des sciences cognitives Marc Jeannerod (for 19 months)
  • Observatoire des Sciences de l Univers de Grenoble (for 16 months)
  • Tem Innovations GmbH (for 11 months)
  • WordFinder.pro (for 10 months)
  • CNRS DT INSU R sif (for 9 months)
  • Alter Way

Like each month, have a look at the work funded by Freexian s Debian LTS offering. Debian project funding Two [1, 2] projects are in the pipeline now. Tryton project is in a final phase. Gradle projects is fighting with technical difficulties. In May, we put aside 2233 EUR to fund Debian projects. We re looking forward to receive more projects from various Debian teams! Learn more about the rationale behind this initiative in this article. Debian LTS contributors In May, 14 contributors have been paid to work on Debian LTS, their reports are available:

• Abhijith PA did 14.0h (out of 14h assigned).
• Andreas R nnquist did 14.5h (out of 25.0h assigned), thus carrying over 10.5h to June.
• Anton Gladky did 19h (out of 19h assigned).
• Ben Hutchings did 8h (out of 11h assigned and 13h from April), thus carrying over 16h to June.
• Chris Lamb did 18h (out of 18h assigned).
• Dominik George did 2h (out of 20.0h assigned), thus carrying over 18h to June.
• Enrico Zini did 9.5h (out of 16.0h assigned), thus carrying over 6.5h to June.
• Emilio Pozuelo Monfort did 28h (out of 13.75h assigned and 35.25h from April), thus carrying over 21h to June.
• Markus Koschany did 40h (out of 40h assigned).
• Roberto C. S nchez did 13.5h (out of 32h assigned), thus carrying over 18.5h to June.
• Sylvain Beucler did 23.5h (out of 20h assigned and 20h from April), thus carrying over 16.5h to June.
• Stefano Rivera did 5h in April and 14h in May (out of 17.5h assigned), thus anticipating 1.5h for June.
• Thorsten Alteholz did 40h (out of 40h assigned).
• Utkarsh Gupta did 35h (out of 19h assigned and 30h from April), thus carrying over 14h to June.

Evolution of the situation In May we released 49 DLAs. The security tracker currently lists 71 packages with a known CVE and the dla-needed.txt file has 65 packages needing an update. The number of paid contributors increased significantly, we are pleased to welcome our latest team members: Andreas R nnquist, Dominik George, Enrico Zini and Stefano Rivera. It is worth pointing out that we are getting close to the end of the LTS period for Debian 9. After June 30th, no new security updates will be made available on security.debian.org. We are preparing to overtake Debian 10 Buster for the next two years and to make this process as smooth as possible. But Freexian and its team of paid Debian contributors will continue to maintain Debian 9 going forward for the customers of the Extended LTS offer. If you have Debian 9 servers to keep secure, it s time to subscribe! You might not have noticed, but Freexian formalized a mission statement where we explain that our purpose is to help improve Debian. For this, we want to fund work time for the Debian developers that recently joined Freexian as collaborators. The Extended LTS and the PHP LTS offers are built following a model that will help us to achieve this if we manage to have enough customers for those offers. So consider subscribing: you help your organization but you also help Debian! Thanks to our sponsors Sponsors that joined recently are in bold.

• Platinum sponsors:
  • TOSHIBA (for 81 months)
  • GitHub (for 72 months)
  • Civil Infrastructure Platform (CIP) (for 49 months)
• Gold sponsors:
  • Roche Diagnostics International AG (for 92 months)
  • Linode (for 86 months)
  • Babiel GmbH (for 75 months)
  • Plat Home (for 75 months)
  • University of Oxford (for 31 months)
  • Deveryware (for 18 months)
  • VyOS Inc (for 13 months)
  • EDF SA
• Silver sponsors:
  • The Positive Internet Company (for 97 months)
  • Domeneshop AS (for 96 months)
  • Nantes M tropole (for 90 months)
  • Univention GmbH (for 82 months)
  • Universit Jean Monnet de St Etienne (for 82 months)
  • Ribbon Communications, Inc. (for 76 months)
  • Exonet B.V. (for 66 months)
  • Leibniz Rechenzentrum (for 60 months)
  • CINECA (for 49 months)
  • Minist re de l Europe et des Affaires trang res (for 43 months)
  • Cloudways Ltd (for 33 months)
  • Dinahosting SL (for 31 months)
  • Bauer Xcel Media Deutschland KG (for 25 months)
  • Platform.sh (for 25 months)
  • Moxa Intelligence Co., Ltd. (for 19 months)
  • sipgate GmbH (for 16 months)
  • OVH US LLC (for 14 months)
  • Tilburg University (for 14 months)
  • GSI Helmholtzzentrum f r Schwerionenforschung GmbH (for 6 months)
  • Telecats BV (for 4 months)
  • Soliton Systems K.K. (for 3 months)
• Bronze sponsors:
  • Evolix (for 97 months)
  • Seznam.cz, a.s. (for 97 months)
  • Intevation GmbH (for 94 months)
  • Linuxhotel GmbH (for 94 months)
  • Daevel SARL (for 92 months)
  • Bitfolk LTD (for 91 months)
  • Megaspace Internet Services GmbH (for 91 months)
  • Greenbone Networks GmbH (for 90 months)
  • NUMLOG (for 90 months)
  • WinGo AG (for 90 months)
  • Ecole Centrale de Nantes LHEEA (for 86 months)
  • Entr ouvert (for 81 months)
  • Adfinis AG (for 78 months)
  • GNI MEDIA (for 73 months)
  • Laboratoire LEGI UMR 5519 / CNRS (for 73 months)
  • Tesorion (for 73 months)
  • Bearstech (for 64 months)
  • LiHAS (for 64 months)
  • People Doc (for 61 months)
  • Catalyst IT Ltd (for 59 months)
  • Supagro (for 54 months)
  • Demarcq SAS (for 53 months)
  • Universit Grenoble Alpes (for 39 months)
  • TouchWeb SAS (for 31 months)
  • SPiN AG (for 28 months)
  • CoreFiling (for 23 months)
  • Institut des sciences cognitives Marc Jeannerod (for 18 months)
  • Observatoire des Sciences de l Univers de Grenoble (for 15 months)
  • Tem Innovations GmbH (for 10 months)
  • WordFinder.pro (for 9 months)
  • CNRS DT INSU R sif (for 8 months)
  • Alter Way

About a month later than I probably should have posted it, here s a recap of my Free Software activities in 2021. For previous years see 2019 + 2020. Again, this year had fewer contributions than I d like thanks to continuing fatigue about the state of the world, and trying to work on separation between work and leisure while working from home. I ve made some effort to improve that balance but it s still a work in progress.

Conferences No surprise, I didn t attend any in-person conferences in 2021. I find virtual conferences don t do a lot for me (a combination of my not carving time out for them in the same way, because not being at the conference means other things will inevitably intrude, and the lack of the social side) but I did get to attend a few of the DebConf21 talks, which was nice. I m hoping to make it to DebConf22 this year in person.

Debian Most of my contributions to Free software continue to happen within Debian. As part of the Data Protection Team I responded to various inbound queries to that team. Some of this involved chasing up other project teams who had been slow to respond - folks, if you re running a service that stores personal data about people then you need to be responsive to requests about it. Some of this was dealing with what look like automated scraping tools which send no information about the person making the request, and in all the cases we ve seen so far there s been no indication of any data about that person on any systems we have access to. Further team time was wasted dealing with the Princeton-Radboud Study on Privacy Law Implementation (though Matthew did the majority of the work on this). The Debian Keyring was possibly my largest single point of contribution. We re in a roughly 3 month rotation of who handles the keyring updates, and I handled 2021.03.24, 2021.04.09, 2021.06.25, 2021.09.25 + 2021.12.24 For Debian New Members I m mostly inactive as an application manager - we generally seem to have enough available recently. If that changes I ll look at stepping in to help, but I don t see that happening. I continue to be involved in Front Desk, having various conversations throughout the year with the rest of the team, but there s no doubt Mattia and Pierre-Elliott are the real doers at present. I did take part in an NM Committee appeals process. In terms of package uploads I continued to work on gcc-xtensa-lx106, largely doing uploads to deal with updates to the GCC version or packaging (8 + 9). sigrok had a few minor updates, libsigkrok 0.5.2-3, pulseview 0.4.2-3 as well as a new upstream release of sigrok CLI 0.7.2-1. There was a last minute pre-release upload of libserialport 0.1.1-4 thanks to a kernel change in v5.10.37 which removed termiox support. Despite still not writing any VHDL these days I continue to keep an eye on ghdl, because I found it a useful tool in the past. Last year that was just a build fix for LLVM 11.1.0 - 1.0.0+dfsg+5. Andreas Bombe has largely taken over more proactive maintenance, which is nice to see. I uploaded OpenOCD 0.11.0~rc1-2, cleaning up some packaging / dependency issues. This was followed by 0.11.0~rc2-1 as a newer release candidate. Sadly 0.11.0 did not make it in time for bullseye, but rc2 was fairly close and I uploaded 0.11.0-1 once bullseye was released. Finally I did a drive-by upload for garmin-forerunner-tools 0.10repacked-12, cleaning up some packaging issues and uploading it to salsa. My Forerunner 305 has died (after 11 years of sterling service) and the Forerunner 45 I ve replaced it with uses a different set of tools, so I decided it didn t make sense to pick up longer term ownership of the package.

Linux My Linux contributions continued to revolve around pushing MikroTik RB3011 support upstream. There was a minor code change to Set FIFO sizes for ipq806x (which fixed up the allowed MTU for the internal switch + VLANs). The rest was DTS related - adding ADM DMA + NAND definitions now that the ADM driver was merged, adding tsens details, adding USB port info and adding the L2CC and RPM details for IPQ8064. Finally I was able to update the RB3011 DTS to enable NAND + USB. With all those in I m down to 4 local patches against a mainline kernel, all of which are hacks that aren t suitable for submission upstream. 2 are for patching in details of the root device and ethernet MAC addresses, one is dealing with the fact the IPQ8064 has some reserved memory that doesn t play well with AUTO_ZRELADDR (there keeps being efforts to add some support for this via devicetree, but unfortunately it gets shot down every time), and the final one is a hack to turn off the LCD backlight by treating it as an LED (actually supporting the LCD properly is on my TODO list).

Personal projects 2021 didn t see any releases of onak. It s not dead, just resting, but Sequoia PGP is probably where you should be looking for a modern OpenPGP implementation. I continued work on my Desk Viking project, which is an STM32F103 based debug tool inspired by the Bus Pirate. The main addtion was some CCLib support (forking it in the process to move to Python 3 and add some speed ups) to allow me to program my Zigbee dongles, but I also added some 1-Wire search logic and some support for Linux emulation mode with VCD output to allow for a faster development cycle. I really want to try and get OpenOCD JTAG mode supported at some point, and have vague plans for an STM32F4 based version that have suffered from a combination of a silicon shortage and a lack of time. That wraps up 2021. I d like to say I m hoping to make more Free Software contributions this year, but I don t have a concrete plan yet for how that might happen, so I ll have to wait and see.

Getting the latest version of a package into Debian involves checking when there are new versions available fortunately (and not surprisingly) Debian has tools to make this simpler. I have recently ran into the problem when an upstream beta version sorts higher than a newer non-beta version. Which is problematic, of course. This is due to Debian sorting something like 1.0b as later than a pure 1.0 version.

gusnan@debian-i7:~ > dpkg --compare-versions 1.0b lt 1.0 && echo true
gusnan@debian-i7:~ > dpkg --compare-versions 1.0b gt 1.0 && echo true
true

But there s a solution name the beta versions something like 1.0~beta. And you don t need to force upstream to make any changes either. You can use uscan and the watch file to make it interpret an upstream 1.0b version as 1.0~beta in Debian. This is done by using a line like

uversionmangle=s/(\d)[\_\.\-\+]?((RC rc pre dev beta alpha b a)\d*)$/$1~$2/;s/\~b/\~beta/;,\

in uversionmangle in your debian/watch file. In this case i have added on the end something to make the ending ~b into ~beta instead. Full version of the watch file available here.

The Motoko programming language has a built-in data type for optional values, named ?t with values null and ?v (for v : t); this is the equivalent of Haskell s Maybe, Ocaml s option or Rust s Option. In this post, I explain how Motoko represents such optional values (almost) without allocation. I neither claim nor expect that any of this is novel; I just hope it s interesting.

Uniform representation The Motoko programming language, designed by Andreas Rossberg and implemented by a pretty cool team at DFINITY is a high-level language with strict semantics and a strong, structural, equi-recursive type system that compiles down to WebAssembly. Because the type system supports polymorphism, it represents all values uniformly. Simplified for the purpose of this blog post, they are always pointers into a heap object where the first word of the heap object, the heap tag, contains information about the value:

 
  tag    
 

The tag is something like array, int64, blob, variant, record, , and it has two purposes:

• The garbage collector uses it to understand what kind of object it is looking at, so that it can move it around and follow pointers therein. Variable size objects such as arrays include the object size in a subsequent word of the heap object.
• Some types have values that may have different shapes on the heap. For example, the ropes used in our text representation can either be a plain blob, or a concatenation node of two blobs. For these types, the tag of the heap object is inspected.

The optional type, naively The optional type (?t) is another example of such a type: Its values can either be null, or ?v for some value v of type t, and the primitive operations on this type are the two introduction forms, an analysis function, and a projection for non-null values:

null : () -> ?t
some : t -> ?t
is_some : ?t -> bool
project : ?t -> t     // must only be used if is_some holds

It is natural to use the heap tag to distinguish the two kind of values:

• The null value is a simple one-word heap object with just a tag that says that this is null:

   
    null  
   

• The other values are represented by a two-word object: The tag some, indicating that it is a ?v, and then the payload, which is the pointer that represents the value v:

   
    some   payload  
   

With this, the four operations can be implemented as follows:

def null():
  ptr <- alloc(1)
  ptr[0] = NULL_TAG
  return ptr
def some(v):
  ptr <- alloc(2)
  ptr[0] = SOME_TAG
  ptr[1] = v
  return ptr
def is_some(p):
  return p[0] == SOME_TAG
def project(p):
  return p[1]

The problem with this implementation is that null() and some(v) both allocate memory. This is bad if they are used very often, and very liberally, and this is the case in Motoko: For example the iterators used for the for (x in e) construct have type

type Iter<T> =   next : () -> ?T  

and would unavoidably allocate a few words on each iteration. Can we avoid this?

Static values It is quite simple to avoid this for for null: Just statically create a single null value and use it every time:

static_null = [NULL_TAG]
def null():
  return static_null

This way, at least null() doesn t allocate. But we gain more: Now every null value is represented by the same pointer, and since the pointer points to static memory, it does not change even with a moving garbage collector, so we can speed up is_some:

def is_some(p):
  return p != static_null

This is not a very surprising change so far, and most compilers out there can and will do at least the static allocation of such singleton constructors. For example, in Haskell, there is only a single empty list ([]) and a single Nothing value in your program, as you can see in my videos exploring the Haskell heap. But can we get rid of the allocation in some(v) too?

Unwrapped optional values If we don t want to allocate in some(v), what can we do? How about simply

def some(v):
  return v

That does not allocate! But it is also broken. At type ??Int, the values null, ?null and ??null are distinct values, but here this breaks. Or, more formally, the following laws should hold for our four primitive operations:

1. is_some(null()) = false
2. v. is_some(some(v)) = true
3. p. project(some(p)) = p

But with the new definition of some, we d get is_some(some(null())) = false. Not good! But note that we only have a problem if we are wrapping a value that is null or some(v). So maybe take the shortcut only then, and write the following:

def some(v):
  if v == static_null   v[0] == SOME_TAG:
    ptr <- alloc(2)
    ptr[0] = SOME_TAG
    ptr[1] = v
    return ptr
  else:
    return v

The definition of is_some can stay as it is: It is still the case that all null values are represented by static_null. But the some values are now no longer all of the same shape, so we have to change project():

def project(p):
  if p[0] == SOME_TAG:
    return p[1]
  else:
    return p

Now things fall into place: A value ?v can, in many cases, be represented the same way as v, and no allocation is needed. Only when v is null or ?null or ??null or ???null etc. we need to use the some heap object, and thus have to allocate. In fact, it doesn t cost much to avoid allocation even for ?null:

static_some_null = [SOME_TAG, static_null]
def some(v):
  if v == static_null:
    return static_some_null
  else if v[0] == SOME_TAG:
    ptr <- alloc(2)
    ptr[0] = SOME_TAG
    ptr[1] = v
    return ptr
  else:
    return v

So unless one nests the ? type two levels deep, there is no allocation whatsoever, and the only cost is a bit more branching in some and project. That wasn t hard, but quite rewarding, as one can now use idioms like the iterator shown above with greater ease.

Examples The following tables shows the representation of various values before and after. Here [ ] is a pointed-to dynamically allocated heap object, a statically allocated heap object, N = NULL_TAG and S = SOME_TAG.

type	value	before	after
Null	null	N	N
?Int	null	N	N
?Int	?23	[S,23]	23
??Int	null	N	N
??Int	?null	[S, N ]	S, N
??Int	??23	[S,[S,23]]	23
???Int	null	N	N
???Int	?null	[S, N ]	S, N
???Int	??null	[S,[S, N ]]	[S, S, N ]
???Int	???23	[S,[S,[S,23]]]	23

Concluding remarks

• If you know what parametric polymorphism is, and wonder how this encoding can work in a language that has that, note that this representation is on the low-level of the untyped run-time value representation: We don t need to know the type of v in some(v), merely its heap representation.
• The uniform representation in Motoko is a bit more involved: The pointers are tagged (by subtracting 1) and some scalar values are represented directly in place (shifted left by 1 bit). But this is luckily orthogonal to what I showed here.
• Could Haskell do this for its Maybe type? Not so easily:
  • The Maybe type is not built-in, but rather a standard library-defined algebraic data type. But the compiler could feasible detect that this is option-like?
  • Haskell is lazy, so at runtime, the type Maybe could be Nothing, or Just v, or, and this is crucial, a yet to be evaluated expression, also called a thunk. And one definitely needs to distinguish between a thunk t :: Maybe a that may evaluate to Nothing, and a value Just t :: Maybe a that definitely is Just, but contains a value, which may be a thunk.
  Something like this may work for a strict Maybe type or unlifted sums like (# (# #) a #), but may clash with other ticks in GHC, such as pointer tagging.
• As I said above, I don t expect this to be novel, and I am happy to add references to prior art here.
• Given that a heap object with tag SOME_TAG now always encodes a tower ? null for n>0, one could try to optimize that even more by just storing the n:

   
    some    n   
   

  But that seems unadvisable: It is only a win if you have deep towers, which is probably rare. Worse, now the project function would have to return such a heap object with n decremented, so now projection might have to allocate, which goes against the cost model expected by the programmer.
• If you rather want to see code than blog posts, feel free to check out Motoko PR #2115.
• Does this kind of stuff excite you? Motoko is open source, so your contributions may be welcome!

Focus This month I didn't have any particular focus. I just worked on issues in my info bubble.

Changes

• libpst: header validity check improvement
• iotop: fix getting syscall numbers
• purple-discord: fix line endings
• ptp-gadget: fix typo, https
• wayback-machine-downloader: fix typos, https, JSON output, gitignore, URL creation, API parsing
• duck: indicator phrases
• check-all-the-things: verbosity variation for yamllint, chktex, rubocop, podchecker
• Debian package uploads: purple-discord, sptag
• Debian wiki pages: AdditionalDebianMailingLists, BSP/2021/05/online, DebianHosting, DebianInstaller/Qemu, DebianKeyring, DebianLocations, DebianSpamAssassin, DebianWiki (EditorGuide, MaintenanceTools, ObsoleteText), Derivatives/Guidelines, DeveloperNews, Dovecot, GraphicsCard, Hardware/Wanted, HowToIdentifyADevice/PCI, initramfs, IRC, LoongArch, LunaJernberg, MemberBenefits, PaulWise, PipeWire, Ports, (ia64, loongarch64), PortsDocs/New, PortTemplate, Redmine, RISC-V, sbuild, Seamonkey, systemd, Teams (DebianMaintainerKeyringTeam, Outreach)
• FOSSjobs wiki pages: Resources
• Wikipedia: Asahi (1 2), Message-ID

Issues

• Crash in purple-discord
• Missing source in Open-Sauce-Fonts
• Building at install time in purple-discord
• Memory leak in purple-discord
• AppArmor denials in clamav-freshclam
• Features in diffoscope, trash-cli
• New versions of ddccontrol
• Build failures when using ognibuild: iotop cmake-hello-world
• Broken watch file for hexedit
• Packaging intended for esprima-python
• Unused deps in sptag
• Incorrect build dir in sptag
• Incorrect docs in sptag
• Large git-lfs data in sptag
• Test problems in sptag (1 2), hexedit

Review

• Spam: reported 1 LWN comment, 26 Debian bug reports and 124 Debian mailing list posts
• Debian wiki: RecentChanges for the month
• Debian BTS usertags: changes for the month
• Debian screenshots:
  • approved e2fsprogs sane util-linux wlogout esekeyd ext4magic lxqt xfce4-clipman
  • rejected netselect (random Android app)

Administration

• Debian wiki: unblock IP addresses, approve accounts

Communication

• Joined the great IRC migration
• Respond to queries from Debian users and contributors on the mailing lists and IRC

Sponsors The purple-discord, sptag and esprima-python work was sponsored by my employer. All other work was done on a volunteer basis.