This post is very late, but better late than never! I want to take a look back at the work that was done on FreedomBox during 2022. Several apps were added to FreedomBox in 2022. The email server app (that was developed by a Google Summer of Code student back in 2021) was finally made available to the general audience of FreedomBox users. You will find it under the name Postfix/Dovecot , which are the main services configured by this app. Another app that was added is Janus, which has the description video room . It is called video room instead of video conference because the room itself is persistent. People can join the room or leave, but there isn t a concept of calling or ending the call . Actually, Janus is a lightweight WebRTC server that can be used as a backend for many different types of applications. But as implemented currently, there is just the simple video room app. In the future, more advanced apps such as Jangouts may be packaged in Debian and made available to FreedomBox. RSS-Bridge is an app that generates RSS feeds for websites that don t provide their own (for example, YouTube). It can be used together with any RSS news feed reader application, such as TT-RSS which is also available in FreedomBox. There is now a Privacy page in the System menu, which allows enabling or disabling the Debian popularity-contest tool. If enabled, it reports the Debian packages that are installed on the system. The results can be seen at https://popcon.debian.org, which currently shows over 400 FreedomBoxes are reporting data. A major feature added to FreedomBox in 2022 is the ability to uninstall apps. This feature is still considered experimental (it won t work for every app), but many issues have been fixed already. There is an option to take a backup of the app s data before uninstalling. There is also now an operations queue in case the user starts multiple install or uninstall operations concurrently. XEP-0363 (HTTP File Upload) has been enabled for Ejabberd Chat Server. This allows files to be transferred between XMPP clients that support this feature. There were a number of security improvements to FreedomBox, such as adding fail2ban jails for Dovecot, Matrix Synapse, and WordPress. Firewall rules were added to ensure that authentication and authorization for services proxied through Apache web server cannot be bypassed by programs running locally on the system. Also, we are no longer using libpam-tmpdir to provide temporary folder isolation, because it causes issues for several packages. Instead we use systemd s sandboxing features, which provide even better isolation for services. Some things were removed in 2022. The ez-ipupdate package is no longer used for Dynamic DNS, since it is replaced by a Python implementation of GnuDIP. An option to restrict who can log in to the system was removed, due to various issues that arose from it. Instead there is an option to restrict who can login through SSH. The DNSSEC diagnostic test was removed, because it caused confusion for many users (although use of DNSSEC is still recommended). Finally, some statistics. There were 31 releases in 2022 (including
point releases). There were 68 unique contributors to the git
repository; this includes code contributions and translations (but not
contributions to the manual pages). In total, there were 980 commits to the git repository.

Prologue For over a year now, Fre(i)e Software GmbH (my company) is involved in Ubuntu Touch development. The development effort currently is handled by a mix of paid and voluntary developers/contributors under the umbrella of the UBports Foundation. We are approaching the official first release of Ubuntu Touch 20.04 with rapid pace. And, if you are a non-Englisch native speaker, we'd like to ask you for help... Read below. light+love
Mike (aka sunweaver at debian.org, Mastodon, IRC, etc.) Internationalization (i18n) of Ubuntu Touch 20.04 The UBports team has moved most of the translation workflows for localizing Ubuntu Touch over to Hosted Weblate:

• https://hosted.weblate.org/projects/lomiri/
• https://hosted.weblate.org/projects/ayatana-indicators/
• https://hosted.weblate.org/projects/ubports/
• https://hosted.weblate.org/projects/open-store-io/

To contribute to the UBports projects you need to register here:

• https://hosted.weblate.org/accounts/register/

The localization platform of all UBports / Lomiri components is sponsored by Hosted Weblate via their free hosting plan for Libre and Open Source Projects. Many thanks for providing this service. Translating Lomiri The translation components in the Lomiri project have already been set up and are ready for being updated by translators. Please expect some translation template changes for all those components to occur in the near future, but this should not hinder you from starting translation work right away. Translating Lomiri will bring the best i18n experience to Ubuntu Touch 20.04 end users for the core libraries and the pre-installed (so called) Core Apps. Translating Ubuntu Touch Apps For App Developers (apps that are not among the Core Apps) we will now offer a translation slot under the UBports project on hosted.weblate.org:

• https://hosted.weblate.org/projects/ubports/

If you are actively maintaining an Ubuntu Touch app, please ask for a translation component slot on hosted.weblate.org and we will set up your app's translation workflow for and with you. Using the translation service at Hosted Weblate is not a must for app developers, it's rather a service we offer to ease i18n work on Ubuntu Touch apps. Who to contact? To get translations for your app set up on Hosted Weblate, please get in touch with us on https://t.me/ubports, please highlight @sunweaver (Mike Gabriel), @BetaBreak (Raoul Kramer), @cibersheep and @Danfro with your request.

The local government here has all the schools use an iCalendar feed for things like when school terms start and stop and other school events occur. The department s website also has events like public holidays. The issue is that all of them don t make it an all-day event but one that happens at midnight, or one past midnight. The events synchronise fine, though Google s calendar is known for synchronising when it feels like it, not at any particular time you would like it to. Why are all the events appearing at midnight? The reason is the feed is incorrectly set up and has the time. The events are sent in an iCalendar format and a typical event looks like this:

BEGIN:VEVENT
DTSTART;TZID=Australia/Sydney:20230206T000000
DTEND;TZID=Australia/Sydney:20230206T000000
SUMMARY:School Term starts
END:VEVENT

The event starting and stopping date and time are the DTSTART and DTEND lines. Both of them have the date of 2023/02/06 or 6th February 2023 and a time of 00:00:00 or midnight. So the calendar is doing the right thing, we need to fix the feed! The Fix I wrote a quick and dirty PHP script to download the feed from the real site, change the DTSTART and DTEND lines to all-day events and leave the rest of it alone.

<?php
$site = $_GET['s'];
if ($site == 'site1')  
    $REMOTE_URL='https://site1.example.net/ical_feed';
  elseif ($site == 'site2')  
    $REMOTE_URL='https://site2.example.net/ical_feed';
  else  
    http_response_code(400);
    die();
 
$fp = fopen($REMOTE_URL, "r");
if (!$fp)  
    die("fopen");
 
header('Content-Type: text/calendar');
while (( $line = fgets($fp, 1024)) !== false)  
    $line = preg_replace(
        '/^(DTSTART DTEND);[^:]+:([0-9] 8 )T000[01]00/',
        '$ 1 ;VALUE=DATE:$ 2 ',
        $line);
    echo $line;
 
?>

It s pretty quick and nasty but gets the job done. So what is it doing?

• Lines 2-10: Check the given variable s and match it to either site1 or site2 to obtain the URL. If you only had one site to fix you could just set the REMOTE_URL variable.
• Lines 12-15: A typical fopen() and nasty error handling.
• Line 16: set the content type to a calendar.
• Line 17: A while loop to read the contents of the remote site line by line.
• Line 18-21: This is where the magic happens, preg_replace is a Perl regular expression replacement. The PCRE is:
  • Finding lines starting with DTSTART or DTEND and store it in capture 1
  • Skip everything that isn t a colon. This is the timezone information. I wasn t sure if it was needed and how to combine it so I took it out. All the all-day events I saw don t have a time zone.
  • Find 8 numerics (this is for YYYYMMDD) and store it in capture 2.
  • Scan the Time part, a literal T then HHMMSS. Some sites use midnight some use one minute past, so it covers both.
  • Replace the line with either DTSTART or DTEND (capture 1), set the value type to DATE as the default is date/time and print the date (capture 2).
• Line 22: Print either the modified or original line.

You need to save the script on your web server somewhere, possibly with an alias command. The whole point of this is to change the type from a date/time to a date-only event and only print the date part of it for the start and end of it. The resulting iCalendar event looks like this:

BEGIN:VEVENT
DTSTART;VALUE=DATE:20230206
DTEND;VALUE=DATE:20230206
SUMMARY:School Term starts
END:VEVENT

The calendar then shows it properly as an all-day event. I would check the script works before doing the next step. You can use things like curl or wget to download it. If you use a normal browser, it will probably just download the translated file. If you re not seeing the right thing then it s probably the PCRE failing. You can check it online with a regex checker such as https://regex101.com. The site has saved my PCRE and match so you got something to start with. Calendar settings The last thing to do is to change the URL in your calendar settings. Each calendar system has a different way of doing it. For Google Calendar they provide instructions and you want to follow the section titled Use a link to add a public Calendar . The URL here is not the actual site s URL (which you would have put into the REMOTE_URL variable before) but the URL of your script plus the ?s=site1 part. So if you put your script aliased to /myical.php and the site ID was site1 and your website is www.example.com the URL would be https://www.example.com/myical.php?s=site1 . You should then see the events appear as all-day events on your calendar.

This is the second of a two-part post covering my goals for 2023. See the first part to understand the vision, mission and strategy driving these goals. I want to thank my friend Nat, and Will Larson whose annual reviews I ve always enjoyed reading for inspiring me to write these posts. I ve found the process articulating my motivations and goals very useful to clarify my thoughts and create tangible next steps. I m grateful for that in and of itself, but I also hope that by publishing this you too might find it interesting, and the additional public accountability it creates will be a positive encouragement to me.

2023 Goals My focus for 2023 is to bootstrap a business that I can use to build software that solves real problems (see the strategy from the previous post for more details on this). I m going to track this via three goals:

1. Execute a series of successful consulting engagements, building a reputation for myself and leaving happy customers willing to provide testimonials that support a pipeline of future opportunities.
2. Grow my product development skill set by taking several ideas to MVP stage with customer feedback received, and launch at least one product which generates revenue and has growth potential.
3. Develop and maintain a broad professional network.

Consulting Based on my background and experience, I plan to target my consulting across three areas:

1. Leadership - building and growing operationally focused software teams following SRE/devops principles. A typical engagement may involve helping a client establish a brand new SRE/devops practice, or to strengthen and mature the existing practices used to build and operate reliable software in their team(s).
2. Architecture - applying deep technical expertise to the design of large software systems, particularly focusing on their reliability and operability. A typical engagement may involve design input and decision making support for key aspects of a new system, providing external review and analysis to improve an existing system, or delivering actionable, tactical next steps during or immediately after a reliability crisis.
3. Technology Strategy - translating high-level business needs into a technical roadmap that provides understandable explanations of the value software can deliver in that context, and the iterative series of appropriately sized projects required to realise it. A typical customer for this would be a small to medium sized business outside of the software industry with a desire to use software in a transformative way to improve their business but who does not employ the necessary in-house expertise to lead that transition.

Product Development There are three, currently extremely high level, product ideas that I m excited to explore:

1. Improve co-ordination of electricity resources to accelerate the electrification of NZ s energy demand and the transition to zero carbon grid. NZ has huge potential to be a world-leader in decarbonising energy use through electrification, but requires a massive transition to realise the benefits. Many of the challenges to that transition involve coordination of an order of magnitude more distributed energy resources (DER) in a much more dynamic and software-oriented manner than the electricity industry is traditionally experienced with. The concept of improving DER coordination is not novel, but our grid has unique characteristics that mean we re likely to need to build localised solutions. There is a strong match between my experience with large, high-reliability distributed software systems, and this need. With renewed motivation in the industry for rapid progress and many conversations and consultations still in their early stages this a very compelling space to explore with the intent of developing a more detailed product opportunity to pursue.
2. Reduce agricultural emissions by making high performance farm management, including effortless compliance reporting, straightforward, fun and effective for busy farmers. NZ s commitments to reduce agricultural emissions (our largest single sector) place increased compliance and reporting burdens on busy farmers who don t want to report the same data multiple times to different regulators and authorities. In tandem, rising business costs and constraints drive a need for continuous improvements in efficiency, performance and farm management processes in order to remain profitable. This in turn drives increases in complexity and the volume of data that farmers must work with. Many industry organisations and associated software developers offer existing products aimed at addressing aspects of these problems, but anecdotal feedback indicates these are poorly integrated, piecemeal solutions that are often frustrating to use - a burden rather than a source of continuous improvement. It looks like there could be an opportunity for a delightful, comprehensive farm management and reporting system to disrupt the industry and help farmers run more profitable and sustainable farms while also reducing compliance costs and effort.
3. Lower sickness rates and improve cognitive performance by enabling every indoor space to benefit from continuous ventilation monitoring and reporting. Indoor air quality is important in reducing disease transmission risk and promoting optimal cognitive performance, but despite the current pandemic temporarily raising its profile, a focus on indoor air quality generally remains under the radar for most people. One factor contributing to this is the lack of widely available systems for continuously monitoring and reporting on air quality. I built https://co2mon.nz/ to help address this problem in my children s school during 2022. I see potential to further grow this business through marketing and raising awareness of the value of ventilation monitoring in all indoor environments.

In addition to these mission aligned product ideas, I m also interested in exploring the creation of small to medium sized SaaS applications that deliver useful value by serving the needs of a specialised or niche business or industry. Even when not directly linked to the overall mission, the development and operation of products of this type can support the strategy. Each application adds direct revenue and also contributes to achieving better economies of scale in the many backend processes and infrastructure required to deliver secure, reliable and performant software systems.

Developing my professional network To help make this goal more actionable and measurable I will track 3 sub goals:

1. To build a professional relationship with at least 30 new people this year, meaning that we ve met and had a decent conversation at least a couple of times and keep in touch at least every few months in some form.
2. To publish a piece of writing on this site at least once a week, and for many of those to generate interesting conversations and feedback. I ll use this as an opportunity to explore product ideas, highlight my consulting expertise and generally contribute interesting technical content into the world.
3. To support the growth of my local technical community by volunteering my experience and knowledge with others through activities such as mentoring, conference talks and similar.

Next Steps Over the coming weeks I ll write more about each of these topics - you can use the box in the sidebar (or on the front page, if you re on a phone) to be notified when I post new writing (there s also an RSS feed here, for the geeks). I d love to have your feedback and engagement on these goals too - please drop me an email with your thoughts or even book a meeting - it won t be a distraction to me, you ll be helping me meet my goal of developing and maintaining my network :)

For the fourth year in a row, I've asked Soci t de Transport de Montr al, Montreal's transit agency, for the foot traffic data of Montreal's subway. By clicking on a subway station, you'll be redirected to a graph of the station's foot traffic.

• Orange line (top10)
• Green line (top10)
• Blue line
• Yellow line
• Global Top 10

Licences

• The subway map displayed on this page, the original dataset and my modified dataset are licenced under CCO 1.0: they are in the public domain.
• The R code I wrote is licensed under the GPLv3+. It's pretty much the same code as last year. I re-used last's year converter script and although I had to clean some of the data by hand, it worked pretty well.

I wanted to look back at what changed in phosh in 2022 and figured I could share it with you. I'll be focusing on things very close to the mobile shell, for a broader overview see Evangelos upcoming FOSDEM talk. Some numbers We're usually aiming for a phosh release at the end of each month. In 2022 We did 10 releases like that, 7 major releases (bumping the middle version number) and three betas. We skipped the April and November releases. We also did one bug fix relesae out of line (bumping the last bit of the version number). I hope we can keep that cadence in 2023 as it allows us to get changes to users in a timely fashion (thus closing usability gaps as early as possible) as well as giving distributions a way to plan ahead. Ideally we'd not skip any release but sometimes real life just interferes. Those releases contain code contributions from about 20 different people and translations from about 30 translators. These numbers are roughly the same as 2021 which is great. Thanks everyone! In phosh's git repository we had a bit over 730 non-merge commits (roughly 2 per day), which is about 10% less than in 2021. Looking closer this is easily compensated by commits to phoc (which needed quite some work for the gestures) and phosh-mobile-settings which didn't exist in 2021. User visible features Most notable new features are likely the swipe gestures for top and bottom bar, the possibility to use the quick settings on the lock screen as well as the style refresh driven by Sam Hewitt that e.g. touched the modal dialogs (but also sliders, dialpads, etc): We also added the possibility to have custom widgets via loadable plugins on the lock screen so the user can decide which information should be available. We currently ship plugins to show

• information on upcoming calendar events
• emergency contact information
• PDFs like bus or train tickets
• the current month (as hello world like plugin to get started)

These are maintained within phosh's source tree although out of tree plugins should be doable too. There's a settings application (the above mentioned phosh-mobile-settings) to enable these. It also allows those plugins to have individual preferences: Speaking of configurability: Scale-to-fit settings (to work around applications that don't fit the screen) and haptic/led feedback are now configurable without resorting to the command line: We can also have device specific settings which helps to temporarily accumulate special workaround without affecting other phones. Other user visible features include the ability to shuffle the digits on the lockscreen's keypad, a VPN quick settings, improved screenshot support and automatic high contrast theme switching when in bright sunlight (based on ambient sensor readings) as shown here. As mentioned above Evangelos will talk at FOSDEM 2023 about the broader ecosystem improvements including GNOME, GTK, wlroots, phoc, feedbackd, ModemManager, mmsd, NetworkManager and many others without phosh wouldn't be possible. What else As I wanted a T-shirt for Debconf 2022 in Prizren so I created a logo heavily inspired by those cute tiger images you often see in Southeast Asia. Based on that I also made a first batch of stickers mostly distributed at FrOSCon 2022: That's it for 2022. If you want to get involved into phosh testing, development or documentation then just drop by in the matrix room.

---

I m migrating some self-hosted virtual machines to Trisquel, and noticed that Trisquel does not offer cloud-images similar to the Debian Cloud and Ubuntu Cloud images. Thus my earlier approach based on virt-install --cloud-init and cloud-localds does not work with Trisquel. While I hope that Trisquel will eventually publish cloud-compatible images, I wanted to document an alternative approach for Trisquel based on preseeding. This is how I used to install Debian and Ubuntu in the old days, and the automated preseed method is best documented in the Debian installation manual. I was hoping to forget about the preseed format, but maybe it will become one of those legacy technologies that never really disappears? Like FAT16 and 8-bit microcontrollers. Below I assume you have a virtual machine host server up that runs libvirt and has virt-install and similar tools; install them with the following command. I run a pre-release version of Trisquel 11 aramo on my VM-host, but I believe any recent dpkg-based distribution like Trisquel 9/10, PureOS 10, Debian 11 or Ubuntu 20.04/22.04 would work.

apt-get install libvirt-daemon-system virtinst genisoimage cloud-image-utils osinfo-db-tools

The approach can install Trisquel 9 (etiona), Trisquel 10 (nabia) and the pre-release of Trisquel 11. First download and verify the integrity of the netinst images that we will need. Unfortunately the Trisquel 11 netinst beta image does not have any checksum or signature available.

mkdir -p /root/iso
cd /root/iso
wget -q https://mirror.fsf.org/trisquel-images/trisquel-netinst_9.0.2_amd64.iso
wget -q https://mirror.fsf.org/trisquel-images/trisquel-netinst_9.0.2_amd64.iso.asc
wget -q https://mirror.fsf.org/trisquel-images/trisquel-netinst_9.0.2_amd64.iso.sha256
wget -q https://mirror.fsf.org/trisquel-images/trisquel-netinst_10.0.1_amd64.iso
wget -q https://mirror.fsf.org/trisquel-images/trisquel-netinst_10.0.1_amd64.iso.asc
wget -q https://mirror.fsf.org/trisquel-images/trisquel-netinst_10.0.1_amd64.iso.sha256
wget -q -O- https://archive.trisquel.info/trisquel/trisquel-archive-signkey.gpg   gpg --import
sha256sum -c trisquel-netinst_9.0.2_amd64.iso.sha256
gpg --verify trisquel-netinst_9.0.2_amd64.iso.asc
sha256sum -c trisquel-netinst_10.0.1_amd64.iso.sha256
gpg --verify trisquel-netinst_10.0.1_amd64.iso.asc
wget -q https://cdbuilds.trisquel.org/aramo/trisquel-netinst_11.0-20221225_amd64.iso
echo '179566639ca8f14f0c3d5658209c59a0916d9e3bf9c026660cc07b28f2311631  trisquel-netinst_11.0-20221225_amd64.iso'   sha256sum -c

I have developed the following fairly minimal preseed file that works with all three Trisquel releases. Compare it against the official Trisquel 11 preseed skeleton and the Debian 11 example preseed file. You should modify obvious things like SSH key, host/IP settings, partition layout and decide for yourself how to deal with passwords. While Ubuntu/Trisquel usually wants to setup a user account, I prefer to login as root hence setting passwd/root-login to true and passwd/make-user to false.

root@trana:~# cat>trisquel.preseed 
d-i debian-installer/locale select en_US
d-i keyboard-configuration/xkb-keymap select us
d-i netcfg/choose_interface select auto
d-i netcfg/disable_autoconfig boolean true
d-i netcfg/get_ipaddress string 192.168.10.201
d-i netcfg/get_netmask string 255.255.255.0
d-i netcfg/get_gateway string 192.168.10.46
d-i netcfg/get_nameservers string 192.168.10.46
d-i netcfg/get_hostname string trisquel
d-i netcfg/get_domain string sjd.se
d-i clock-setup/utc boolean true
d-i time/zone string UTC
d-i mirror/country string manual
d-i mirror/http/hostname string ftp.acc.umu.se
d-i mirror/http/directory string /mirror/trisquel/packages
d-i mirror/http/proxy string
d-i partman-auto/method string regular
d-i partman-partitioning/confirm_write_new_label boolean true
d-i partman/choose_partition select finish
d-i partman/confirm boolean true
d-i partman/confirm_nooverwrite boolean true
d-i partman-basicfilesystems/no_swap boolean false
d-i partman-auto/expert_recipe string myroot :: 1000 50 -1 ext4 \
     $primary    $bootable    method  format   \
     format    use_filesystem    filesystem  ext4   \
     mountpoint  /   \
    .
d-i partman-auto/choose_recipe select myroot
d-i passwd/root-login boolean true
d-i user-setup/allow-password-weak boolean true
d-i passwd/root-password password r00tme
d-i passwd/root-password-again password r00tme
d-i passwd/make-user boolean false
tasksel tasksel/first multiselect
d-i pkgsel/include string openssh-server
popularity-contest popularity-contest/participate boolean false
d-i grub-installer/only_debian boolean true
d-i grub-installer/with_other_os boolean true
d-i grub-installer/bootdev string default
d-i finish-install/reboot_in_progress note
d-i preseed/late_command string mkdir /target/root/.ssh ; echo ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAILzCFcHHrKzVSPDDarZPYqn89H5TPaxwcORgRg+4DagE cardno:FFFE67252015 > /target/root/.ssh/authorized_keys
^D
root@trana:~# 

Use the file above as a skeleton for preparing a VM-specific preseed file as follows. The environment variables HOST and IPS will be used later on too.

root@trana:~# HOST=foo
root@trana:~# IP=192.168.10.197
root@trana:~# sed -e "s,get_ipaddress string.*,get_ipaddress string $IP," -e "s,get_hostname string.*,get_hostname string $HOST," < trisquel.preseed > vm-$HOST.preseed
root@trana:~# 

The following script is used to prepare the ISO images with the preseed file that we will need. This script is inspired by the Debian Wiki Preseed EditIso page and the Trisquel ISO customization wiki page. There are a couple of variations based on earlier works. Paths are updated to match the Trisquel netinst ISO layout, which differ slightly from Debian. We modify isolinux.cfg to boot the auto label without a timeout. On Trisquel 11 the auto boot label exists, but on Trisquel 9 and Trisquel 10 it does not exist so we add it in order to be able to start the automated preseed installation.

root@trana:~# cat gen-preseed-iso 
#!/bin/sh
# Copyright (C) 2018-2022 Simon Josefsson -- GPLv3+
# https://wiki.debian.org/DebianInstaller/Preseed/EditIso
# https://trisquel.info/en/wiki/customizing-trisquel-iso
set -e
set -x
ISO="$1"
PRESEED="$2"
OUTISO="$3"
LASTPWD="$PWD"
test -f "$ISO"
test -f "$PRESEED"
test ! -f "$OUTISO"
TMPDIR=$(mktemp -d)
mkdir "$TMPDIR/mnt"
mkdir "$TMPDIR/tmp"
cp "$PRESEED" "$TMPDIR"/preseed.cfg
cd "$TMPDIR"
mount "$ISO" mnt/
cp -rT mnt/ tmp/
umount mnt/
chmod +w -R tmp/
gunzip tmp/initrd.gz
echo preseed.cfg   cpio -H newc -o -A -F tmp/initrd
gzip tmp/initrd
chmod -w -R tmp/
sed -i "s/timeout 0/timeout 1/" tmp/isolinux.cfg
sed -i "s/default vesamenu.c32/default auto/" tmp/isolinux.cfg
if ! grep -q auto tmp/adtxt.cfg; then
    cat<<EOF >> tmp/adtxt.cfg
label auto
	menu label ^Automated install
	kernel linux
	append auto=true priority=critical vga=788 initrd=initrd.gz --- quiet
EOF
fi
cd tmp/
find -follow -type f   xargs md5sum  > md5sum.txt
cd ..
cd "$LASTPWD"
genisoimage -r -J -b isolinux.bin -c boot.cat \
            -no-emul-boot -boot-load-size 4 -boot-info-table \
            -o "$OUTISO" "$TMPDIR/tmp/"
rm -rf "$TMPDIR"
exit 0
^D
root@trana:~# chmod +x gen-preseed-iso 
root@trana:~# 

Next run the command on one of the downloaded ISO image and the generated preseed file.

root@trana:~# ./gen-preseed-iso /root/iso/trisquel-netinst_10.0.1_amd64.iso vm-$HOST.preseed vm-$HOST.iso
+ ISO=/root/iso/trisquel-netinst_10.0.1_amd64.iso
+ PRESEED=vm-foo.preseed
+ OUTISO=vm-foo.iso
+ LASTPWD=/root
+ test -f /root/iso/trisquel-netinst_10.0.1_amd64.iso
+ test -f vm-foo.preseed
+ test ! -f vm-foo.iso
+ mktemp -d
+ TMPDIR=/tmp/tmp.mNEprT4Tx9
+ mkdir /tmp/tmp.mNEprT4Tx9/mnt
+ mkdir /tmp/tmp.mNEprT4Tx9/tmp
+ cp vm-foo.preseed /tmp/tmp.mNEprT4Tx9/preseed.cfg
+ cd /tmp/tmp.mNEprT4Tx9
+ mount /root/iso/trisquel-netinst_10.0.1_amd64.iso mnt/
mount: /tmp/tmp.mNEprT4Tx9/mnt: WARNING: source write-protected, mounted read-only.
+ cp -rT mnt/ tmp/
+ umount mnt/
+ chmod +w -R tmp/
+ gunzip tmp/initrd.gz
+ echo preseed.cfg
+ cpio -H newc -o -A -F tmp/initrd
5 blocks
+ gzip tmp/initrd
+ chmod -w -R tmp/
+ sed -i s/timeout 0/timeout 1/ tmp/isolinux.cfg
+ sed -i s/default vesamenu.c32/default auto/ tmp/isolinux.cfg
+ grep -q auto tmp/adtxt.cfg
+ cat
+ cd tmp/
+ find -follow -type f
+ xargs md5sum
+ cd ..
+ cd /root
+ genisoimage -r -J -b isolinux.bin -c boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -o vm-foo.iso /tmp/tmp.mNEprT4Tx9/tmp/
I: -input-charset not specified, using utf-8 (detected in locale settings)
Using GCRY_000.MOD;1 for  /tmp/tmp.mNEprT4Tx9/tmp/boot/grub/x86_64-efi/gcry_sha512.mod (gcry_sha256.mod)
Using XNU_U000.MOD;1 for  /tmp/tmp.mNEprT4Tx9/tmp/boot/grub/x86_64-efi/xnu_uuid.mod (xnu_uuid_test.mod)
Using PASSW000.MOD;1 for  /tmp/tmp.mNEprT4Tx9/tmp/boot/grub/x86_64-efi/password_pbkdf2.mod (password.mod)
Using PART_000.MOD;1 for  /tmp/tmp.mNEprT4Tx9/tmp/boot/grub/x86_64-efi/part_sunpc.mod (part_sun.mod)
Using USBSE000.MOD;1 for  /tmp/tmp.mNEprT4Tx9/tmp/boot/grub/x86_64-efi/usbserial_pl2303.mod (usbserial_ftdi.mod)
Using USBSE001.MOD;1 for  /tmp/tmp.mNEprT4Tx9/tmp/boot/grub/x86_64-efi/usbserial_ftdi.mod (usbserial_usbdebug.mod)
Using VIDEO000.MOD;1 for  /tmp/tmp.mNEprT4Tx9/tmp/boot/grub/x86_64-efi/videotest.mod (videotest_checksum.mod)
Using GFXTE000.MOD;1 for  /tmp/tmp.mNEprT4Tx9/tmp/boot/grub/x86_64-efi/gfxterm_background.mod (gfxterm_menu.mod)
Using GCRY_001.MOD;1 for  /tmp/tmp.mNEprT4Tx9/tmp/boot/grub/x86_64-efi/gcry_sha256.mod (gcry_sha1.mod)
Using MULTI000.MOD;1 for  /tmp/tmp.mNEprT4Tx9/tmp/boot/grub/x86_64-efi/multiboot2.mod (multiboot.mod)
Using USBSE002.MOD;1 for  /tmp/tmp.mNEprT4Tx9/tmp/boot/grub/x86_64-efi/usbserial_usbdebug.mod (usbserial_common.mod)
Using MDRAI000.MOD;1 for  /tmp/tmp.mNEprT4Tx9/tmp/boot/grub/x86_64-efi/mdraid09.mod (mdraid09_be.mod)
Size of boot image is 4 sectors -> No emulation
 22.89% done, estimate finish Thu Dec 29 23:36:18 2022
 45.70% done, estimate finish Thu Dec 29 23:36:18 2022
 68.56% done, estimate finish Thu Dec 29 23:36:18 2022
 91.45% done, estimate finish Thu Dec 29 23:36:18 2022
Total translation table size: 2048
Total rockridge attributes bytes: 24816
Total directory bytes: 40960
Path table size(bytes): 64
Max brk space used 46000
21885 extents written (42 MB)
+ rm -rf /tmp/tmp.mNEprT4Tx9
+ exit 0
root@trana:~#

Now the image is ready for installation, so invoke virt-install as follows. The machine will start directly, launching the preseed automatic installation. At this point, I usually click on the virtual machine in virt-manager to follow screen output until the installation has finished. If everything works OK the machines comes up and I can ssh into it.

root@trana:~# virt-install --name $HOST --disk vm-$HOST.img,size=5 --cdrom vm-$HOST.iso --osinfo linux2020 --autostart --noautoconsole --wait
Using linux2020 default --memory 4096
Starting install...
Allocating 'vm-foo.img'                                                                                                                                     0 B  00:00:00 ... 
Creating domain...                                                                                                                                          0 B  00:00:00     
Domain is still running. Installation may be in progress.
Waiting for the installation to complete.
Domain has shutdown. Continuing.
Domain creation completed.
Restarting guest.
root@trana:~# 

There are some problems that I have noticed that would be nice to fix, but are easy to work around. The first is that at the end of the installation of Trisquel 9 and Trisquel 10, the VM hangs after displaying Sent SIGKILL to all processes followed by Requesting system reboot. I kill the VM manually using virsh destroy foo and start it up again using virsh start foo. For production use I expect to be running Trisquel 11, where the problem doesn t happen, so this does not bother me enough to debug further. The remaining issue that once booted, a Trisquel 11 VM has lost its DNS nameserver configuration, presumably due to poor integration with systemd-resolved. Both Trisquel 9 and Trisquel 10 uses systemd-resolved where DNS works after first boot, so this appears to be a Trisquel 11 bug. You can work around it with rm -f /etc/resolv.conf && echo 'nameserver A.B.C.D' > /etc/resolv.conf or drink the systemd Kool-Aid. If you want to clean up and re-start the process, here is how you wipe out what you did. After this, you may run the sed, ./gen-preseed-iso and virt-install commands again. Remember, use virsh shutdown foo to gracefully shutdown a VM.

root@trana:~# virsh destroy foo
Domain 'foo' destroyed
root@trana:~# virsh undefine foo --remove-all-storage
Domain 'foo' has been undefined
Volume 'vda'(/root/vm-foo.img) removed.
root@trana:~# rm vm-foo.*
root@trana:~# 

Happy hacking on your virtal machines!

This post marks the beginning my yearly roundups of the favourite books and movies that I read and watched in 2022 that I plan to publish over the next few days. Just as I did for 2020 and 2021, I won't reveal precisely how many books I read in the last year. I didn't get through as many books as I did in 2021, though, but that's partly due to reading a significant number of long nineteenth-century novels in particular, a fair number of those books that American writer Henry James once referred to as "large, loose, baggy monsters." However, in today's post I'll be looking at my favourite books that are typically filed under fiction, with 'classic' fiction following tomorrow. Works that just missed the cut here include John O'Brien's Leaving Las Vegas, Colson Whitehead's Sag Harbor and possibly The Name of the Rose by Umberto Eco, or Elif Batuman's The Idiot. I also feel obliged to mention (or is that show off?) that I also read the 1,079-page Infinite Jest by David Foster Wallace, but I can't say it was a favourite, let alone recommend others unless they are in the market for a good-quality under-monitor stand.

Mona (2021) Pola Oloixarac Mona is the story of a young woman who has just been nominated for the 'most important literary award in Europe'. Mona sees the nomination as a chance to escape her substance abuse on a Californian campus and so speedily decamps to the small village in the depths of Sweden where the nominees must convene for a week before the overall winner is announced. Mona didn't disappear merely to avoid pharmacological misadventures, though, but also to avoid the growing realisation that she is being treated as something of an anthropological curiosity at her university: a female writer of colour treasured for her flourish of exotic diversity that reflects well upon her department. But Mona is now stuck in the company of her literary competitors who all have now gathered from around the world in order to do what writers do: harbour private resentments, exchange empty flattery, embody the selfsame racialised stereotypes that Mona left the United States to avoid, stab rivals in the back, drink too much, and, of course, go to bed together. But as I read Mona, I slowly started to realise that something else is going on. Why does Mona keep finding traces of violence on her body, the origins of which she cannot or refuses to remember? There is something eerily defensive about her behaviour and sardonic demeanour in general as well. A genre-bending and mind-expanding novel unfolded itself, and, without getting into spoiler territory, Mona concludes with such a surprising ending that, according to Adam Thirlwell:

Perhaps we need to rethink what is meant by a gimmick. If a gimmick is anything that we want to reject as extra or excessive or ill-fitting, then it may be important to ask what inhibitions or arbitrary conventions have made it seem like excess, and to revel in the exorbitant fictional constructions it produces. [...]

Mona is a savage satire of the literary world, but it's also a very disturbing exploration of trauma and violence. The success of the book comes in equal measure from the author's commitment to both ideas, but also from the way the psychological damage component creeps up on you. And, as implied above, the last ten pages are quite literally out of this world.

My Brilliant Friend (2011)
The Story of a New Name (2012)
Those Who Leave and Those Who Stay (2013)
The Story of the Lost Child (2014) Elena Ferrante Elena Ferrante's Neopolitan Quartet follows two girls, both brilliant in their own way. Our protagonist-narrator is Elena, a studious girl from the lower rungs of the middle class of Naples who is inspired to be more by her childhood friend, Lila. Lila is, in turn, far more restricted by her poverty and class, but can transcend it at times through her fiery nature, which also brands her as somewhat unique within their inward-looking community. The four books follow the two girls from the perspective of Elena as they grow up together in post-war Italy, where they drift in-and-out of each other's lives due to the vicissitudes of change and the consequences of choice. All the time this is unfolding, however, the narrative is very always slightly charged by the background knowledge revealed on the very first page that Lila will, many years later, disappear from Elena's life. Whilst the quartet has the formal properties of a bildungsroman, its subject and conception are almost entirely different. In particular, the books are driven far more by character and incident than spectacular adventures in picturesque Italy. In fact, quite the opposite takes place: these are four books where ordinary-seeming occurrences take on an unexpected radiance against a background of poverty, ignorance, violence and other threats, often bringing to mind the films of the Italian neorealism movement. Brilliantly rendered from beginning to end, Ferrante has a seemingly studious eye for interpreting interactions and the psychology of adolescence and friendship. Some utterances indeed, perhaps even some glances are dissected at length over multiple pages, something that Vittorio De Sica's classic Bicycle Thieves (1948) could never do. Potential readers should not take any notice of the saccharine cover illustrations on most editions of the books. The quartet could even win an award for the most misleading artwork, potentially rivalling even Vladimir Nabokov's Lolita. I wouldn't be at all surprised if it is revealed that the drippy illustrations and syrupy blurbs ("a rich, intense and generous-hearted story ") turn out to be part of a larger metatextual game that Ferrante is playing with her readers. This idiosyncratic view of mine is partially supported by the fact that each of the four books has been given a misleading title, the true ambiguity of which often only becomes clear as each of the four books comes into sharper focus. Readers of the quartet often fall into debating which is the best of the four. I've heard from more than one reader that one has 'too much Italian politics' and another doesn't have enough 'classic' Lina moments. The first book then possesses the twin advantages of both establishing the environs and finishing with a breathtaking ending that is both satisfying and a cliffhanger as well but does this make it 'the best'? I prefer to liken the quartet more like the different seasons of The Wire (2002-2008) where, personal favourites and preferences aside, although each season is undoubtedly unique, it would take a certain kind of narrow-minded view of art to make the claim that, say, series one of The Wire is 'the best' or that the season that focuses on the Baltimore docks 'is boring'. Not to sound like a neo-Wagnerian, but each of them adds to final result in its own. That is to say, both The Wire and the Neopolitan Quartet achieve the rare feat of making the magisterial simultaneously intimate.

Out There: Stories (2022) Kate Folk Out There is a riveting collection of disturbing short stories by first-time author Kate Fork. The title story first appeared in the New Yorker in early 2020 imagines a near-future setting where a group of uncannily handsome artificial men called 'blots' have arrived on the San Francisco dating scene with the secret mission of sleeping with women, before stealing their personal data from their laptops and phones and then (quite literally) evaporating into thin air. Folk's satirical style is not at all didactic, so it rarely feels like she is making her points in a pedantic manner. But it's clear that the narrator of Out There is recounting her frustration with online dating. in a way that will resonate with anyone who s spent time with dating apps or indeed the contemporary hyper-centralised platform-based internet in general. Part social satire, part ghost story and part comic tales, the blurring of the lines between these factors is only one of the things that makes these stories so compelling. But whilst Folk constructs crazy scenarios and intentionally strange worlds, she also manages to also populate them with characters that feel real and genuinely sympathetic. Indeed, I challenge you not to feel some empathy for the 'blot' in the companion story Big Sur which concludes the collection, and it complicates any primary-coloured view of the dating world of consisting entirely of predatory men. And all of this is leavened with a few stories that are just plain surreal. I don't know what the deal is with Dating a Somnambulist (available online on Hobart Pulp), but I know that I like it.

Solaris (1961) Stanislaw Lem When Kelvin arrives at the planet Solaris to study the strange ocean that covers its surface, instead of finding an entirely physical scientific phenomenon, he soon discovers a previously unconscious memory embodied in the physical manifestation of a long-dead lover. The other scientists on the space station slowly reveal that they are also plagued with their own repressed corporeal memories. Many theories are put forward as to why all this is occuring, including the idea that Solaris is a massive brain that creates these incarnate memories. Yet if that is the case, the planet's purpose in doing so is entirely unknown, forcing the scientists to shift focus and wonder whether they can truly understand the universe without first understanding what lies within their own minds and in their desires. This would be an interesting outline for any good science fiction book, but one of the great strengths of Solaris is not only that it withholds from the reader why the planet is doing anything it does, but the book is so forcefully didactic in its dislike of the hubris, destructiveness and colonial thinking that can accompany scientific exploration. In one of its most vitriolic passages, Lem's own anger might be reaching out to the reader:

We are humanitarian and chivalrous; we don t want to enslave other races, we simply want to bequeath them our values and take over their heritage in exchange. We think of ourselves as the Knights of the Holy Contact. This is another lie. We are only seeking Man. We have no need of other worlds. We need mirrors. We don t know what to do with other worlds. A single world, our own, suffices us; but we can t accept it for what it is. We are searching for an ideal image of our own world: we go in quest of a planet, of a civilisation superior to our own, but developed on the basis of a prototype of our primaeval past. At the same time, there is something inside us that we don t like to face up to, from which we try to protect ourselves, but which nevertheless remains since we don t leave Earth in a state of primal innocence. We arrive here as we are in reality, and when the page is turned, and that reality is revealed to us that part of our reality that we would prefer to pass over in silence then we don t like it anymore.

An overwhelming preoccupation with this idea infuses Solaris, and it turns out to be a common theme in a lot of Lem's work of this period, such as in his 1959 'anti-police procedural' The Investigation. Perhaps it not a dislike of exploration in general or the modern scientific method in particular, but rather a savage critique of the arrogance and self-assuredness that accompanies most forms of scientific positivism, or at least pursuits that cloak themselves under the guise of being a laudatory 'scientific' pursuit:

Man has gone out to explore other worlds and other civilizations without having explored his own labyrinth of dark passages and secret chambers and without finding what lies behind doorways that he himself has sealed.

I doubt I need to cite specific instances of contemporary scientific pursuits that might meet Lem's punishing eye today, and the fact that his critique works both in 2022 and 1961 perhaps tells us more about the human condition than we'd care to know. Another striking thing about Solaris isn't just the specific Star Trek and Stargate SG-1 episodes that I retrospectively realised were purloined from the book, but that almost the entire register of Star Trek: The Next Generation in particular seems to be rehearsed here. That is to say, TNG presents itself as hard and fact-based 'sci-fi' on the surface, but, at its core, there are often human, existential and sometimes quite enormously emotionally devastating human themes being discussed such as memory, loss and grief. To take one example from many, the painful memories that the planet Solaris physically materialises in effect asks us to seriously consider what it actually is taking place when we 'love' another person: is it merely another 'mirror' of ourselves? (And, if that is the case, is that... bad?) It would be ahistorical to claim that all popular science fiction today can be found rehearsed in Solaris, but perhaps it isn't too much of a stretch:

[Solaris] renders unnecessary any more alien stories. Nothing further can be said on this topic ...] Possibly, it can be said that when one feels the urge for such a thing, one should simply reread Solaris and learn its lessons again. Kim Stanley Robinson [...]

I could go on praising this book for quite some time; perhaps by discussing the extreme framing devices used within the book at one point, the book diverges into a lengthy bibliography of fictional books-within-the-book, each encapsulating a different theory about what the mechanics and/or function of Solaris is, thereby demonstrating that 'Solaris studies' as it is called within the world of the book has been going on for years with no tangible results, which actually leads to extreme embarrassment and then a deliberate and willful blindness to the 'Solaris problem' on the part of the book's scientific community. But I'll leave it all here before this review gets too long... Highly recommended, and a likely reread in 2023.

Brokeback Mountain (1997) Annie Proulx Brokeback Mountain began as a short story by American author Annie Proulx which appeared in the New Yorker in 1997, although it is now more famous for the 2005 film adaptation directed by Taiwanese filmmaker Ang Lee. Both versions follow two young men who are hired for the summer to look after sheep at a range under the 'Brokeback' mountain in Wyoming. Unexpectedly, however, they form an intense emotional and sexual attachment, yet life intervenes and demands they part ways at the end of the summer. Over the next twenty years, though, as their individual lives play out with marriages, children and jobs, they continue reuniting for brief albeit secret liaisons on camping trips in remote settings. There's no feigned shyness or self-importance in Brokeback Mountain, just a close, compassionate and brutally honest observation of a doomed relationship and a bone-deep feeling for the hardscrabble life in the post-War West. To my mind, very few books have captured so acutely the desolation of a frustrated and repressed passion, as well as the particular flavour of undirected anger that can accompany this kind of yearning. That the original novella does all this in such a beautiful way (and without the crutch of the Wyoming landscape to look at ) is a tribute to Proulx's skills as a writer. Indeed, even without the devasting emotional undertones, Proulx's descriptions of the mountains and scree of the West is likely worth the read alone.

Luster (2020) Raven Leilani Edie is a young Black woman living in New York whose life seems to be spiralling out of control. She isn't good at making friends, her career is going nowhere, and she has no close family to speak of as well. She is, thus, your typical NYC millennial today, albeit seen through a lens of Blackness that complicates any reductive view of her privilege or minority status. A representative paragraph might communicate the simmering tone:

Before I start work, I browse through some photos of friends who are doing better than me, then an article on a black teenager who was killed on 115th for holding a weapon later identified as a showerhead, then an article on a black woman who was killed on the Grand Concourse for holding a weapon later identified as a cell phone, then I drown myself in the comments section and do some online shopping, by which I mean I put four dresses in my cart as a strictly theoretical exercise and then let the page expire.

She starts a sort-of affair with an older white man who has an affluent lifestyle in nearby New Jersey. Eric or so he claims has agreed upon an 'open relationship' with his wife, but Edie is far too inappropriate and disinhibited to respect any boundaries that Eric sets for her, and so Edie soon becomes deeply entangled in Eric's family life. It soon turns out that Eric and his wife have a twelve-year-old adopted daughter, Akila, who is also wait for it Black. Akila has been with Eric's family for two years now and they aren t exactly coping well together. They don t even know how to help her to manage her own hair, let alone deal with structural racism. Yet despite how dark the book's general demeanour is, there are faint glimmers of redemption here and there. Realistic almost to the end, Edie might finally realise what s important in her life, but it would be a stretch to say that she achieves them by the final page. Although the book is full of acerbic remarks on almost any topic (Dogs: "We made them needy and physically unfit. They used to be wolves, now they are pugs with asthma."), it is the comments on contemporary race relations that are most critically insightful. Indeed, unsentimental, incisive and funny, Luster had much of what I like in Colson Whitehead's books at times, but I can't remember a book so frantically fast-paced as this since the Booker-prize winning The Sellout by Paul Beatty or Sam Tallent's Running the Light.

Foreword Freexian has been using Tryton for a few years to handle its invoicing and accounting. We have thus also been using the Debian packages maintained by Mathias Behrle and we have been funding some of his work because maintaining an ERP with more than 50 source packages was too much for him to handle alone on his free time. When Mathias discovered our Project Funding initiative, it was quite natural for him to consider applying to be able to bring some much needed improvements to Tryton s Debian packaging. He s running his own consulting company (MBSolutions) so it s easy for him to invoice Freexian to get the money for the funded projects. What follows is Mathias Behrle s description of the projects that he submitted and of the work that he achieved. If you want to contact him, you can reach out to mathiasb@m9s.biz or mbehrle@debian.org. You can also follow him on Mastodon.

Report In January 2022 I applied for two projects in the Freexian Project Funding Initiative.

• Tryton Project 1
  • The starting point of this project was Debian Bug #998319: tryton-server should provide a ready-to-use production-grade server config. To address this problem instead of only providing configuration snippets the idea was to provide a full featured guided setup of a Tryton production environment, thus eliminating the risks of trial and error for the system administrator.
• Tryton Project 2
  • The goal of this project was to complete the available Tryton modules in Debian main with the latest set available from tryton.org and to automate the task of creating new Debian packages from Tryton modules as much as possible.

Accomplishments As the result of Task 1, several new packages emerged:

• tryton-server-postgresql provides the guided setup of a PostgreSQL database backend.
• tryton-server-uwsgi provides the installation and configuration of a robust WSGI server on top of tryton-server.
• tryton-server-nginx provides the configuration of a scalable web frontend to the uwsgi server, including the optional setup of secure access by Letsencrypt certificates.
• tryton-server-all-in-one puts it all together to provide a fully functional Tryton production environment, including a database filled with basic static data. With the installation of this package a robust and secure production grade setup is possible from scratch, all configuration leg work is done in the background.

The work was thoroughly reviewed by Neil Williams. Thanks go to him for his detailed feedback providing very valuable information from the view of a fresh Tryton user getting in first contact with the software. A cordial thank you as well goes to the translation teams providing initial reviews and translations for the configuration questions. The efforts of Task 1 were completed with Task 2:

• A Tryton specific version of PyPi2deb was created to help in the preparation of new Debian packages for new Tryton modules.
• All missing Tryton modules for the current series were packaged for Debian.

On top of those two planned projects, I completed an additional task: the packaging of the Tryton Web Client. The Web Client is a quite important feature to access a Tryton server with the browser and even a crucial requirement for some companies. Unfortunately the packaging of the Web Client for Debian was problematic from the beginning. tryton-sao requires exact versions of JavaScript libraries that are almost never guaranteed to be available in the different targeted Debian releases. Therefore a package with vendored libraries has been created and will hopefully soon hit the Debian main archive. The package is already available from the Tryton Backport Mirror for the usually supported Debian releases.

Summary I am very pleased that the Tryton suite in Debian has gained full coverage of Tryton modules and a user-friendly installation. The completion of the project represents a huge step forward in the state-of-the-art deployment of a production grade Tryton environment. Without the monetary support of Freexian s project funding the realization of this project wouldn t have been possible in this way and to this extent.

I ran into what seemed to be a DNS problem when building a Docker container:

Err http://archive.ubuntu.com jammy Release.gpg
  Could not resolve 'archive.ubuntu.com'
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/jammy/Release.gpg  Could not resolve 'archive.ubuntu.com'
W: Some index files failed to download. They have been ignored, or old ones used instead.

I found that many solutions talked about setting the default DNS server explicitly in /etc/docker/daemon.json:

 
    "dns": ["1.1.1.1"]
 

but that didn't work for me. I noticed however that I was having these problems whenever I connected to my VPN. So what did work for me was restarting the docker daemon whenever there is a change in networking (e.g. enabling/disabling VPN) by putting the following in /etc/NetworkManager/dispatcher.d/docker-local:

#!/bin/sh
LOGFILE=/var/log/docker-restarts.log
if [ -z "$1" ]; then
    echo "$0: called with no interface" >> $LOGFILE
    exit 1;
fi
if [ "$1" = lo ]; then
    # Ignoring the loopback interface
    exit 0;
fi
case "$2" in
    up vpn-up down vpn-down)
        echo "$0: restarting docker due to action \ $2' on interface \ $1'" >> $LOGFILE
        /bin/systemctl restart docker.service
        ;;
    *)
        echo "$0: ignoring action \ $2' on interface \ $1'" >> $LOGFILE
        ;;
esac

and then making that new file executable:

chmod +x /etc/NetworkManager/dispatcher.d/docker-local

You can confirm that it's working as intended by watching the logs:

tail -f /var/log/docker-restarts.log

while enabling/disable your VPN or your network connection. If you don't see any output, then something is wrong and the Docker restart isn't happening.

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.

From November 2nd to 4th, 2022, the 19th edition of Latinoware - Latin American Congress of Free Software and Open Technologies took place in Foz do Igua u. After 2 years happening online due to the COVID-19 pandemic, the event was back in person and we felt Debian Brasil community should be there. Out last time at Latinoware was in 2016 The Latinoware organization provided the Debian Brazil community with a booth so that we could have contact with people visiting the open exhibition area and thus publicize the Debian project. During the 3 days of the event, the booth was organized by me (Paulo Henrique Santana) as Debian Developer, and by Leonardo Rodrigues as Debian contributor. Unfortunately Daniel Lenharo had an issue and could not travel to Foz do Igua u (we miss you there!). A huge number of people visited the booth, and the beginners (mainly students) who didn't know Debian, asked what our group was about and we explained various concepts such as what Free Software is, GNU/Linux distribution and Debian itself. We also received people from the Brazilian Free Software community and from other Latin American countries who were already using a GNU/Linux distribution and, of course, many people who were already using Debian. We had some special visitors as Jon maddog Hall, Debian Developer Emeritus Ot vio Salvador, Debian Developer Eriberto Mota, and Debian Maintainers Guilherme de Paula Segundo and Paulo Kretcheu. Photo from left to right: Leonardo, Paulo, Eriberto and Ot vio. Photo from left to right: Paulo, Fabian (Argentina) and Leonardo. In addition to talking a lot, we distributed Debian stickers that were produced a few months ago with Debian's sponsorship to be distributed at DebConf22 (and that were left over), and we sold several Debian t-shirts) produced by Curitiba Livre community). We also had 3 talks included in Latinoware official schedule. I) talked about: "how to become a Debian contributor by doing translations" and "how the SysAdmins of a global company use Debian". And Leonardo) talked about: "advantages of Open Source telephony in companies". Photo Paulo in his talk. Many thanks to Latinoware organization for once again welcoming the Debian community and kindly providing spaces for our participation, and we congratulate all the people involved in the organization for the success of this important event for our community. We hope to be present again in 2023. We also thank Jonathan Carter for approving financial support from Debian for our participation at Latinoware. Portuguese version

From November 2nd to 4th, 2022, the 19th edition of Latinoware - Latin American Congress of Free Software and Open Technologies took place in Foz do Igua u. After 2 years happening online due to the COVID-19 pandemic, the event was back in person and we felt Debian Brasil community should be there. Out last time at Latinoware was in 2016 The Latinoware organization provided the Debian Brazil community with a booth so that we could have contact with people visiting the open exhibition area and thus publicize the Debian project. During the 3 days of the event, the booth was organized by me (Paulo Henrique Santana) as Debian Developer, and by Leonardo Rodrigues as Debian contributor. Unfortunately Daniel Lenharo had an issue and could not travel to Foz do Igua u (we miss you there!). A huge number of people visited the booth, and the beginners (mainly students) who didn't know Debian, asked what our group was about and we explained various concepts such as what Free Software is, GNU/Linux distribution and Debian itself. We also received people from the Brazilian Free Software community and from other Latin American countries who were already using a GNU/Linux distribution and, of course, many people who were already using Debian. We had some special visitors as Jon maddog Hall, Debian Developer Emeritus Ot vio Salvador, Debian Developer Eriberto Mota, and Debian Maintainers Guilherme de Paula Segundo and Paulo Kretcheu. Photo from left to right: Leonardo, Paulo, Eriberto and Ot vio. Photo from left to right: Paulo, Fabian (Argentina) and Leonardo. In addition to talking a lot, we distributed Debian stickers that were produced a few months ago with Debian's sponsorship to be distributed at DebConf22 (and that were left over), and we sold several Debian t-shirts) produced by Curitiba Livre community). We also had 3 talks included in Latinoware official schedule. I) talked about: "how to become a Debian contributor by doing translations" and "how the SysAdmins of a global company use Debian". And Leonardo) talked about: "advantages of Open Source telephony in companies". Photo Paulo in his talk. Many thanks to Latinoware organization for once again welcoming the Debian community and kindly providing spaces for our participation, and we congratulate all the people involved in the organization for the success of this important event for our community. We hope to be present again in 2023. We also thank Jonathan Carter for approving financial support from Debian for our participation at Latinoware. Portuguese version

A new release 0.2.12 of RcppCCTZ is now on CRAN. RcppCCTZ uses Rcpp to bring CCTZ to R. CCTZ is a C++ library for translating between absolute and civil times using the rules of a time zone. In fact, it is two libraries. One for dealing with civil time: human-readable dates and times, and one for converting between between absolute and civil times via time zones. And while CCTZ is made by Google(rs), it is not an official Google product. The RcppCCTZ page has a few usage examples and details. This package was the first CRAN package to use CCTZ; by now several others packages (four the last time we counted) include its sources too. Not ideal, but beyond our control. This version adds support for NA values when parsing, and updates GitHub Action.

Changes in version 0.2.12 (2022-11-06)

• Support NA values in numerical or character input
• GitHub Actions were updated to checkout version 3.

Courtesy of my CRANberries, there is also a diffstat to the previous version. More details are at the RcppCCTZ page; code, issue tickets etc at the GitHub repository. If you like this or other open-source work I do, you can now sponsor me at GitHub.

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.

Shantaram I know I have been quite behind in review of books but then that s life. First up is actually not as much as a shocker but somewhat of a pleasant surprise. So, a bit of background before I share the news. If you have been living under a rock, then about 10-12 years ago a book called Shantaram was released. While the book is said to have been released in 2003/4 I got it in my hand around 2008/09 or somewhere around that. The book is like a good meal, a buffet. To share the synopsis, Lin a 20 something Australian guy gets involved with a girl, she encourages him to get into heroin, he becomes a heroin user. And drugs, especially hard drugs need constant replenishment, it is a chemical thing. So, to fund those cravings, he starts to steal, rising to rob a bank and while getting away shoots a cop who becomes dead. Now either he surrenders or is caught is unclear, but he is tortured in the jail. So one day, he escapes from prison, lands up at home of somebody who owes him a favor, gets some money, gets a fake passport and lands up in Mumbai/Bombay as it was then known. This is from where the actual story starts. And how a 6 foot something Australian guy relying on his street smartness and know how the transformation happens from Lin to Shantaram. Now what I have shared is perhaps just 5% of the synopsis, as shared the real story starts here. Now the good news, last week 4 episodes of Shantaram were screened by Apple TV. Interestingly, I have seen quite a number people turning up to buy or get this book and also sharing it on Goodreads. Now there seems to have been some differences from the book to TV. Now I m relying on 10-12 year back memory but IIRC Khaderbhai, one of the main characters who sort of takes Lin/Shantaram under his wing is an Indian. In the series, he is a western or at least looks western/Middle Eastern to me. Also, they have tried to reproduce 1980s in Mumbai/Bombay but dunno how accurate they were My impression of that city from couple of visits at that point in time where they were still more tongas (horse-ridden carriages), an occasional two wheelers and not many three wheelers. Although, it was one of the more turbulent times as lot of agitation for worker rights were happening around that time and a lot of industrial action. Later that led to lot of closure of manufacturing in Bombay and it became more commercial. It would be interesting to know whether they shot it in actual India or just made a set somewhere in Australia, where it possibly might have been shot. The chawl of the book needs a bit of arid land and Australia has lots of it. It is also interesting as this was a project that had who s who interested in it for a long time but somehow none of them was able to bring the project to fruition, the project seems to largely have an Australian cast as well as second generations of Indians growing in Australia. To take names, Amitabh Bacchan, Johnny Depp, Russel Crowe each of them wanted to make it into a feature film. In retrospect, it is good it was not into a movie, otherwise they would have to cut a lot of material and that perhaps wouldn t have been sufficient. Making it into a web series made sure they could have it in multiple seasons if people like it. There is a lot between now and 12 episodes to even guess till where it would leave you then. So, if you have not read the book and have some holidays coming up, can recommend it. The writing IIRC is easy and just flows. There is a bit of action but much more nuance in the book while in the web series they are naturally more about action. There is also quite a bit of philosophy between him and Kaderbhai and while the series touches upon it, it doesn t do justice but then again it is being commercially made. Read the book, see the series and share your thoughts on what you think. It is possible that the series might go up or down but am sharing from where I see it, may do another at the end of the season, depending on where they leave it and my impressions. Update A slight update from the last blog post. Seems Rishi Sunak seems would be made PM of UK. With Hunt as chancellor and Rishi Sunak, Austerity 2.0 seems complete. There have been numerous articles which share how austerity gives rises to fascism and vice-versa. History gives lot of lessons about the same. In Germany, when the economy was not good, it was all blamed on the Jews for number of years. This was the reason for rise of Hitler, and while it did go up by a bit, propaganda by him and his loyalists did the rest. And we know and have read about the Holocaust. Today quite a few Germans deny it or deny parts of it but that s how misinformation spreads. Also Hitler is looked now more as an aberration rather than something to do with the German soul. I am not gonna talk more as there is still lots to share and that actually perhaps requires its own blog post to do justice for the same.

The Pyramid by Henning Mankell I had actually wanted to review this book but then the bomb called Shantaram appeared and I had to post it above. I had read two-three books before it, but most of them were about multiple beheadings and serial killers. Enough to put anybody into depression. I do not know if modern crime needs to show crime and desperation of and to such a level. Why I and most loved and continue to love Sherlock Holmes as most stories were not about gross violence but rather a homage to the art of deduction, which pretty much seems to be missing in modern crime thrillers rather than grotesque stuff. In that, like a sort of fresh air I read/am reading the Pyramid by Henning Mankell. The book is about a character made by Monsieur Henning Mankell named Kurt Wallender. I am aware of the series called Wallender but haven t yet seen it. The book starts with Wallender as a beat cop around age 20 and on his first case. He is ambitious, wants to become a detective and has a narrow escape with death. I wouldn t go much into it as it basically gives you an idea of the character and how he thinks and what he does. He is more intuitive by nature and somewhat of a loner. Probably most detectives IRL are, dunno, have no clue. At least in the literary world it makes sense, in real world think there would be much irony for sure. This is speculation on my part, who knows. Back to the book though. The book has 5 stories a sort of prequel one could say but also not entirely true. The first case starts when he is a beat cop in 1969 and he is just a beat cop. It is a kind of a prequel and a kind of an anthology as he covers from the first case to the 1990s where he is ending his career sort of. Before I start sharing about the stories in the book, I found the foreword also quite interesting. It asks questions about the interplay of the role of welfare state and the Swedish democracy. Incidentally did watch couple of videos about a sort of mixed sort of political representation that happens in Sweden. It uses what is known as proportional representation. Ironically, Sweden made a turn to the far right this election season. The book was originally in Swedish and were translated to English by Ebba Segerberg and Laurie Thompson. While all the stories are interesting, would share the last three or at least ask the questions of intrigue. Of course, to answer them you would need to read the book So the last three stories I found the most intriguing. The first one is titled Man on the Beach. Apparently, a gentleman goes to one of the beaches, a sort of lonely beach, hails a taxi and while returning suddenly dies. The Taxi driver showing good presence of mind takes it to hospital where the gentleman is declared dead on arrival. Unlike in India, he doesn t run away but goes to the cafeteria and waits there for the cops to arrive and take his statement. Now the man is in his early 40s and looks to be fit. Upon searching his pockets he is found to relatively well-off and later it turns out he owns a couple of shops. So then here are the questions ? What was the man doing on a beach, in summer that beach is somewhat popular but other times not so much, so what was he doing there? How did he die, was it a simple heart attack or something more? If he had been drugged or something then when and how? These and more questions can be answered by reading the story Man on the Beach . 2. The death of a photographer Apparently, Kurt lives in a small town where almost all the residents have been served one way or the other by the town photographer. The man was polite and had worked for something like 40 odd years before he is killed/murdered. Apparently, he is murdered late at night. So here come the questions a. The shop doesn t even stock any cameras and his cash box has cash. Further investigation reveals it is approximate to his average takeout for the day. So if it s not for cash, then what is the motive ? b. The body was discovered by his cleaning staff who has worked for almost 20 years, 3 days a week. She has her own set of keys to come and clean the office? Did she give the keys to someone, if yes why? c. Even after investigation, there is no scandal about the man, no other woman or any vices like gambling etc. that could rack up loans. Also, nobody seems to know him and yet take him for granted till he dies. The whole thing appears to be quite strange. Again, the answers lie in the book. 3. The Pyramid Kurt is sleeping one night when the telephone rings. The scene starts with a Piper Cherokee, a single piston aircraft flying low and dropping something somewhere or getting somebody from/on the coast of Sweden. It turns and after a while crashes. Kurt is called to investigate it. Turns out, the plane was supposed to be destroyed. On crash, both the pilot and the passenger are into pieces so only dental records can prove who they are. Same day or a day or two later, two seemingly ordinary somewhat elderly women, spinsters, by all accounts, live above the shop where they sell buttons and all kinds of sewing needs of the town. They seem middle-class. Later the charred bodies of the two sisters are found :(. So here come the questions a.Did the plane drop something or pick something somebody up ? The Cherokee is a small plane so any plane field or something it could have landed up or if a place was somehow marked then could be dropped or picked up without actually landing. b. The firefighter suspects arson started at multiple places with the use of petrol? The question is why would somebody wanna do that? The sisters don t seem to be wealthy and practically everybody has bought stuff from them. They weren t popular but weren t also unpopular. c. Are the two crimes connected or unconnected? If connected, then how? d. Most important question, why the title Pyramid is given to the story. Why does the author share the name Pyramid. Does he mean the same or the original thing? He could have named it triangle. Again, answers to all the above can be found in the book. One thing I also became very aware of during reading the book that it is difficult to understand people s behavior and what they do. And this is without even any criminality involved in. Let s say for e.g. I die in some mysterious circumstances, the possibility of the police finding my actions in last days would be limited and this is when I have hearing loss. And this probably is more to do with how our minds are wired. And most people I know are much more privacy conscious/aware than I am.

Japan s Hikikomori Japan has been a curious country. It was more or less a colonizer and somewhat of a feared power till it dragged the U.S. unnecessarily in World War 2. The result of the two atom bombs and the restitution meant that Japan had to build again from the ground up. It is also in a seismically unstable place as they have frequent earthquakes although the buildings are hardened/balanced to make sure that vibrations don t tear buildings apart. Had seen years ago on Natgeo a documentary that explains all that. Apart from that, Japan was helped by the Americans and there was good kinship between them till the 1980s till it signed the Plaza Accord which enhanced asset price bubbles that eventually burst. Something from which they are smarting even today. Japan has a constitutional monarchy. A somewhat history lesson or why it exists even today can be found here. Asset price bubbles of the 1980s, more than 50 percent of the population on zero hour contracts and the rest tend to suffer from overwork. There is a term called Karoshi that explains all. An Indian pig-pen would be two, two and a half times larger than a typical Japanese home. Most Japanese live in micro-apartments called konbachiku . All of the above stresses meant that lately many young Japanese people have become Hikikomori. Bloomberg featured about the same a couple of years back. I came to know about it as many Indians are given the idea of Japan being a successful country without knowing the ills and issues it faces. Even in that most women get the wrong end of the short stick i.e. even it they manage to find jobs, it would be most back-breaking menial work. The employment statistics of Japan s internal ministry tells its own story.

If you look at the data above, it seems that the between 2002 and 2019, the share of zero hour contracts has increased while regular work has decreased. This also means that those on the bottom of the ladder can no longer afford a home. There is and was a viral video called Lost in Manboo that went viral few years ago. It is a perfect set of storms. Add to that the Fukushima nuclear incident about which I had shared a few years ago. While the workers are blamed but all design decisions are taken by the management. And as was shown in numerous movies, documentaries etc. Interestingly, and somewhat ironically, the line workers knew the correct things to do and correct decisions to take unlike the management. The shut-ins story is almost a decade or two decades old. It is similar story in South Korea but not as depressive as the in Japan. It is somewhat depressive story but needed to be shared. The stories shared in the bloomberg article makes your heart ache

Backpacks In and around 2015, I had bought a Targus backpack, very much similar to the Targus TSB194US-70 Motor 16-inch Backpack. That bag has given me a lot of comfort over the years but now has become frayed the zip sometimes work and sometimes doesn t. Unlike those days there are a bunch of companies now operating in India. There are eight different companies that I came to know about, Aircase, Harrisons Sirius, HP Oddyssey, Mokobara, Artic Hunter, Dell Pro Hybrid, Dell Roller Backpack and lastly the Decathlon Quechua Hiking backpack 32L NH Escape 500 . Now of all the above, two backpacks seem the best, the first one is Harrisons Sirius, with 45L capacity, I don t think I would need another bag at all. The runner-up is the Decathlon Quecha Hiking Backpack 32L. One of the better things in all the bags is that all have hidden pockets for easy taking in and out of passport while having being ant-theft. I do not have to stress how stressful it is to take out the passport and put it back in. Almost all the vendors have made sure that it is not a stress point anymore. The good thing about the Quecha is that they are giving 10 years warranty, the point to be asked is if that is does the warranty cover the zip. Zips are the first thing that goes out in bags.That actually has what happened to my current bag. Decathlon has a store in Wakad, Pune while I have reached out to the gentleman in charge of Harrisons India to see if they have a reseller in Pune. So hopefully, in next one week I should have a backpack that isn t spilling with things all over the place, whichever I m able to figure out.

This is my report from the Netfilter Workshop 2022. The event was held on 2022-10-20/2022-10-21 in Seville, and the venue was the offices of Zevenet. We started on Thursday with Pablo Neira (head of the project) giving a short welcome / opening speech. The previous iteration of this event was in virtual fashion in 2020, two years ago. In the year 2021 we were unable to meet either in person or online. This year, the number of participants was just eight people, and this allowed the setup to be a bit more informal. We had kind of an un-conference style meeting, in which whoever had something prepared just went ahead and opened a topic for debate. In the opening speech, Pablo did a quick recap on the legal problems the Netfilter project had a few years ago, a topic that was settled for good some months ago, in January 2022. There were no news in this front, which was definitely a good thing. Moving into the technical topics, the workshop proper, Pablo started to comment on the recent developments to instrument a way to perform inner matching for tunnel protocols. The current implementation supports VXLAN, IPIP, GRE and GENEVE. Using nftables you can match packet headers that are encapsulated inside these protocols. He mentioned the design and the goals, that was to have a kernel space setup that allows adding more protocols by just patching userspace. In that sense, more tunnel protocols will be supported soon, such as IP6IP, UDP, and ESP. Pablo requested our opinion on whether if nftables should generate the matching dependencies. For example, if a given tunnel is UDP-based, a dependency match should be there otherwise the rule won t work as expected. The agreement was to assist the user in the setup when possible and if not, print clear error messages. By the way, this inner thing is pure stateless packet filtering. Doing inner-conntracking is an open topic that will be worked on in the future. Pablo continued with the next topic: nftables automatic ruleset optimizations. The times of linear ruleset evaluation are over, but some people have a hard time understanding / creating rulesets that leverage maps, sets, and concatenations. This is where the ruleset optimizations kick in: it can transform a given ruleset to be more optimal by using such advanced data structures. This is purely about optimizing the ruleset, not about validating the usefulness of it, which could be another interesting project. There were a couple of problems mentioned, however. The ruleset optimizer can be slow, O(n!) in worst case. And the user needs to use nested syntax. More improvements to come in the future. Next was Stefano Brivio s turn (Red Hat engineer). He had been involved lately in a couple of migrations to nftables, in particular libvirt and KubeVirt. We were pointed to https://libvirt.org/firewall.html, and Stefano walked us through the 3 or 4 different virtual networks that libvirt can create. He evaluated some options to generate efficient rulesets in nftables to instrument such networks, and commented on a couple of ideas: having a null matcher in nftables set expression. Or perhaps having kind of subsets, something similar to a view in a SQL database. The room spent quite a bit of time debating how the nft_lookup API could be extended to support such new search operations. We also discussed if having intermediate facilities such as firewalld could provide the abstraction levels that could make developers more comfortable. Using firewalld also may have the advantage that coordination between different system components writing ruleset to nftables is handled by firewalld itself and developers are freed of the responsibility of doing it right. Next was Fernando F. Mancera (Red Hat engineer). He wanted to improve error reporting when deleting table/chain/rules with nftables. In general, there are some inconsistencies on how tables can be deleted (or flushed). And there seems to be no correct way to make a single table go away with all its content in a single command. The room agreed in that the commands destroy table and delete table should be defined consistently, with the following meanings:

• destroy: nuke the table, don t fail if it doesn t exist
• delete: delete the table, but the command will fail if it doesn t exist

This topic diverted into another: how to reload/replace a ruleset but keep stateful information (such as counters). Next was Phil Sutter (Netfilter coreteam member and Red Hat engineer). He was interested in discussing options to make iptables-nft backward compatible. The use case he brought was simple: What happens if a container running iptables 1.8.7 creates a ruleset with features not supported by 1.8.6. A later container running 1.8.6 may fail to operate. Phil s first approach was to attach additional metadata into rules to assist older iptables-nft in decoding and printing the ruleset. But in general, there are no obvious or easy solutions to this problem. Some people are mixing different tooling version, and there is no way all cases can be predicted/covered. iptables-nft already refuses to work in some of the most basic failure scenarios. An other way to approach the issue could be to introduce some kind of support to print raw expressions in iptables-nft, like -m nft xyz. Which feels ugly, but may work. We also explored playing with the semantics of release version numbers. And another idea: store strings in the nft rule userdata area with the equivalent matching information for older iptables-nft. In fact, what Phil may have been looking for is not backwards but forward compatibility. Phil was undecided which path to follow, but perhaps the most common-sense approach is to fall back to a major release version bump (2.x.y) and declaring compatibility breakage with older iptables 1.x.y. That was pretty much it for the first day. We had dinner together and went to sleep for the next day. The second day was opened by Florian Westphal (Netfilter coreteam member and Red Hat engineer). Florian has been trying to improve nftables performance in kernels with RETPOLINE mitigations enabled. He commented that several workarounds have been collected over the years to avoid the performance penalty of such mitigations. The basic strategy is to avoid function indirect calls in the kernel. Florian also described how BPF programs work around this more effectively. And actually, Florian tried translating nf_hook_slow() to BPF. Some preliminary benchmarks results were showed, with about 2% performance improvement in MB/s and PPS. The flowtable infrastructure is specially benefited from this approach. The software flowtable infrastructure already offers a 5x performance improvement with regards the classic forwarding path, and the change being researched by Florian would be an addition on top of that. We then moved into discussing the meeting Florian had with Alexei in Zurich. My personal opinion was that Netfilter offers interesting user-facing interfaces and semantics that BPF does not. Whereas BPF may be more performant in certain scenarios. The idea of both things going hand in hand may feel natural for some people. Others also shared my view, but no particular agreement was reached in this topic. Florian will probably continue exploring options on that front. The next topic was opened by Fernando. He wanted to discuss Netfilter involvement in Google Summer of Code and Outreachy. Pablo had some personal stuff going on last year that prevented him from engaging in such projects. After all, GSoC is not fundamental or a priority for Netfilter. Also, Pablo mentioned the lack of support from others in the project for mentoring activities. There was no particular decision made here. Netfilter may be present again in such initiatives in the future, perhaps under the umbrella of other organizations. Again, Fernando proposed the next topic: nftables JSON support. Fernando shared his plan of going over all features and introduce programmatic tests from them. He also mentioned that the nftables wiki was incomplete and couldn t be used as a reference for missing tests. Phil suggested running the nftables python test-suite in JSON mode, which should complain about missing features. The py test suite should cover pretty much all statements and variations on how the nftables expression are invoked. Next, Phil commented on nftables xtables support. This is, supporting legacy xtables extensions in nftables. The most prominent problem was that some translations had some corner cases that resulted in a listed ruleset that couldn t be fed back into the kernel. Also, iptables-to-nftables translations can be sloppy, and the resulting rule won t work in some cases. In general, nft list ruleset nft -f may fail in rulesets created by iptables-nft and there is no trivial way to solve it. Phil also commented on potential iptables-tests.py speed-ups. Running the test suite may take very long time depending on the hardware. Phil will try to re-architect it, so it runs faster. Some alternatives had been explored, including collecting all rules into a single iptables-restore run, instead of hundreds of individual iptables calls. Next topic was about documentation on the nftables wiki. Phil is interested in having all nftables code-flows documented, and presented some improvements in that front. We are trying to organize all developer-oriented docs on a mediawiki portal, but the extension was not active yet. Since I worked at the Wikimedia Foundation, all the room stared at me, so at the end I kind of committed to exploring and enabling the mediawiki portal extension. Note to self: is this perhaps https://www.mediawiki.org/wiki/Portals ? Next presentation was by Pablo. He had a list of assorted topics for quick review and comment.

• We discussed nftables accept/drop semantics. People that gets two or more rulesets from different software are requesting additional semantics here. A typical case is fail2ban integration. One option is quick accept (no further evaluation if accepted) and the other is lazy drop (don t actually drop the packet, but delay decision until the whole ruleset has been evaluated). There was no clear way to move forward with this.
• A debate on nft userspace memory usage followed. Some people are running nftables on low end devices with very little memory (such as 128 MB). Pablo was exploring a potential solution: introducing struct constant_expr, which can reduce 12.5% mem usage.
• Next we talked about repository licensing (or better, relicensing to GPLv2+). Pablo went over a list of files in the nftables tree which had diverging licenses. All people in the room agreed on this relicensing effort. A mention to the libreadline situation was made.
• Another quick topic: a bogus EEXIST in nft_rbtree. Pablo & Stefano to work in a patch.
• Next one was conntrack early drop in flowtable. Pablo is studying use cases for some legitimate UDP unidirectional flows (like RTP traffic).
• Pablo and Stefano discussed pipapo not being atomic on updates. Stefano already looked into it, and one of the ideas was to introduce a new commit API for sets.
• The last of the quick topics was an idea to have a global table in nftables. Or some global items, like sets. Folk in the community keep asking for this. Some ideas were discussed, like perhaps adding a family agnostic family. But then there would be a challenge: nftables would need to generate byte code that works in any of the hooks. There was no immediate way of addressing this. The idea of having templated tables/sets circulated again as a way of reusing data across namespaces/families.

Following this, a new topic was introduced by Stefano. He wanted to talk about nft_set_pipapo, documentation, what to do next, etc. He did a nice explanation of how the pipapo algorithm works for element inserts, lookups, and deletion. The source code is pretty well documented, by the way. He showed performance measurements of different data types being stored in the structure. After some lengthly debate on how to introduce changes without breaking usage for users, he declared some action items: writing more docs, addressing problems with non-atomic set reloads and a potential rework of nft_rbtree. After that, the next topic was kubernetes & netfilter , also by Stefano. Actually, this topic was very similar to what we already discussed regarding libvirt. Developers want to reduce packet matching effort, but also often don t leverage nftables most performant features, like sets, maps or concatenations. Some Red Hat developers are already working on replacing everything with native nftables & firewalld integrations. But some rules generators are very bad. Kubernetes (kube-proxy) is a known case. Developers simply won t learn how to code better ruleset generators. There was a good question floating around: What are people missing on first encounter with nftables? The Netfilter project doesn t have a training or marketing department or something like that. We cannot force-educate developers on how to use nftables in the right way. Perhaps we need to create a set of dedicated guidelines, or best practices, in the wiki for app developers that rely on nftables. Jozsef Kadlecsik (Netfilter coreteam) supported this idea, and suggested going beyond: such documents should be written exclusively from the nftables point of view: stop approaching the docs as a comparison to the old iptables semantics. Related to that last topic, next was Laura Garc a (Zevenet engineer, and venue host). She shared the same information as she presented in the Kubernetes network SIG in August 2020. She walked us through nftlb and kube-nftlb, a proof-of-concept replacement for kube-proxy based on nftlb that can outperform it. For whatever reason, kube-nftlb wasn t adopted by the upstream kubernetes community. She also covered latest changes to nftlb and some missing features, such as integration with nftables egress. nftlb is being extended to be a full proxy service and a more robust overall solution for service abstractions. In a nutshell, nftlb uses a templated ruleset and only adds elements to sets, which is exactly the right usage of the nftables framework. Some other projects should follow its example. The performance numbers are impressive, and from the early days it was clear that it was outperforming classical LVS-DSR by 10x. I used this opportunity to bring a topic that I wanted to discuss. I ve seen some SRE coworkers talking about katran as a replacement for traditional LVS setups. This software is a XDP/BPF based solution for load balancing. I was puzzled about what this software had to offer versus, for example, nftlb or any other nftables-based solutions. I commented on the highlighs of katran, and we discussed the nftables equivalents. nftlb is a simple daemon which does everything using a JSON-enabled REST API. It is already packaged into Debian, ready to use, whereas katran feels more like a collection of steps that you need to run in a certain order to get it working. All the hashing, caching, HA without state sharing, and backend weight selection features of katran are already present in nftlb. To work on a pure L3/ToR datacenter network setting, katran uses IPIP encapsulation. They can t just mangle the MAC address as in traditional DSR because the backend server is on a different L3 domain. It turns out nftables has a nft_tunnel expression that can do this encapsulation for complete feature parity. It is only available in the kernel, but it can be made available easily on the userspace utility too. Also, we discussed some limitations of katran, for example, inability to handle IP fragmentation, IP options, and potentially others not documented anywhere. This seems to be common with XDP/BPF programs, because handling all possible network scenarios would over-complicate the BPF programs, and at that point you are probably better off by using the normal Linux network stack and nftables. In summary, we agreed that nftlb can pretty much offer the same as katran, in a more flexible way. Finally, after many interesting debates over two days, the workshop ended. We all agreed on the need for extending it to 3 days next time, since 2 days feel too intense and too short for all the topics worth discussing. That s all on my side! I really enjoyed this Netfilter workshop round.

More ICFP-inspired experiments using the rec-def library: In Norman Ramsey s very nice talk about his Functional Pearl Beyond Relooper: Recursive Translation of Unstructured Control Flow to Structured Control Flow , he had the following slide showing the equation for the dominators of a node in a graph:

Norman Ramsey shows a formula

He said it s ICFP and I wanted to say the dominance relation has a beautiful set of equations you can read all these algorithms how to compute this, but the concept is simple . This made me wonder: If the concept is simple and this formula is beautiful shouldn t this be sufficient for the Haskell programmer to obtain the dominator relation, without reading all those algorithms? Before we start, we have to clarify the formula a bit: If a node is an entry node (no predecessors) then the big intersection is over the empty set, and that is not a well-defined concept. For these nodes, we need that big intersection to return the empty set, as entry nodes are not dominated by any other node. (Let s assume that the entry nodes are exactly those with no predecessors.) Let s try, first using plain Haskell data structures. We begin by implementing this big intersection operator on Data.Set, and also a function to find the predecessors of a node in a graph: Now we can write down the formula that Norman gave, quite elegantly: Does this work? It seems it does: But not surprising if you have read my previous blog posts it falls over once we have recursion: So let us reimplement it with Data.Recursive.Set. The hope is that we can simply replace the operations, and that now it can suddenly handle cyclic graphs as well. Let s see: It does! Well, it does return a result but it looks strange. Clearly node 3 and 4 are also dominated by 1, but the result does not reflect that. But the result is a solution to Norman s equation. Was the equation wrong? No, but we failed to notice that the desired solution is the largest, not the smallest. And Data.Recursive.Set calculates, as documented, the least fixed point. What now? Until the library has code for RDualSet a, we can work around this by using the dual formula to calculate the non-dominators. To do this, we

• use union instead of intersection
• delete instead of insert,
• S.empty, use the set of all nodes (which requires some extra plumbing)
• subtract the result from the set of all nodes to get the dominators

and thus the code turns into: And with this, now we do get the correct result:

ghci> domintors3 [(1,2),(1,3),(2,4),(3,4),(4,3)]
fromList [(1,[1]),(2,[1,2]),(3,[1,3]),(4,[1,4])]

We worked a little bit on how to express the beautiful formula to Haskell, but at no point did we have to think about how to solve it. To me, this is the essence of declarative programming.

(The picture is of the previous edition.) Almost two years after the previous Norwegian Bokm l translation of the "The Debian Administrator's Handbook" was published, a new edition is finally being prepared. The english text is updated, and it is time to start working on the translations. Around 37 percent of the strings have been updated, one way or another, and the translations starting from a complete Debian Buster edition now need to bring their translation up from 63% to 100%. The complete book is licensed using a Creative Commons license, and has been published in several languages over the years. The translations are done by volunteers to bring Linux in their native tongue. The last time I checked, it complete text was available in English, Norwegian Bokm l, German, Indonesian, Brazil Portuguese and Spanish. In addition, work has been started for Arabic (Morocco), Catalan, Chinese (Simplified), Chinese (Traditional), Croatian, Czech, Danish, Dutch, French, Greek, Italian, Japanese, Korean, Persian, Polish, Romanian, Russian, Swedish, Turkish and Vietnamese. The translation is conducted on the hosted weblate project page. Prospective translators are recommeded to subscribe to the translators mailing list and should also check out the instructions for contributors. I am one of the Norwegian Bokm l translators of this book, and we have just started. Your contribution is most welcome. As usual, if you use Bitcoin and want to show your support of my activities, please send Bitcoin donations to my address 15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b.

Politics I have been reading books, both fiction and non-fiction for a long long time. My first book was a comic most probably when I was down with Malaria when I was a kid. I must be around 4-5 years old. Over the years, books have given me great joy and I continue to find nuggets of useful information, both in fiction as well as non-fiction books. So here s to sharing something and how that can lead you to a rabbit hole. This entry would be a bit NSFW as far as language is concerned. NYPD Red 5 by James Patterson First of all, have no clue as to why James Patterson s popularity has been falling. He used to be right there with Lee Child and others, but not so much now. While I try to be mysterious about books, I would give a bit of heads-up so people know what to expect. This is probably more towards the Adult crowd as there is a bit of sex as well as quite a few grey characters. The NYPD Red is a sort of elite police task force that basically is for celebrities. In the book series, they do a lot of ass-kissing (figuratively more than literally). Now the reason I have always liked fiction is that however wild the assumption or presumption is, it does have somewhere a grain of truth. And each and every time I read a book or two, that gets cemented. One of the statements in the book told something about how 9/11 took a lot of police personnel out of the game. First, there were a number of policemen who were patrolling the Two Towers, so they perished literally during the explosion. Then there were policemen who were given the cases to close the cases (bring the cases to conclusion). When you are investigating your own brethren or even civilians who perished 9/11 they must have experienced emotional trauma and no outlet. Mental health even in cops is the same and given similar help as you and me (i.e. next to none.) But both of these were my assumptions. The only statement that was in the book was they lost a lot of bench strength. Even NYFD (New York Fire Department). This led me to me to With Crime At Record Lows, Should NYC Have Fewer Cops? This is more right-wing sentiment and in fact, there have been calls to defund the police. This led me to https://cbcny.org/ and one specific graph. Unfortunately, this tells the story from 2010-2022 but not before. I was looking for data from around 1999 to 2005 because that will tell whether or not it happened. Then I remembered reading in newspapers the year or two later how 9/11 had led NYC to recession. I looked up online and for sure NY was booming before 9/11. One can argue that NYC could come down and that is pretty much possible, everything that goes up comes down, it s a law of nature but it would have been steady rather than abrupt. And once you are in recession, the first thing to go is personnel. So people both from NYPD and NYFD were let go, even though they were needed the most then. As you can see, a single statement in a book can take you to places & time literally. Edit: Addition 11th September There were quite a few people who also died from New York Port Authority and they also lost quite a number of people directly and indirectly and did a lot of patrolling of the water bodies near NYC. Later on, even in their department, there were a lot of early retirements.

Kosovo A couple of days back I had a look at the Debconf 2023 BOF that was done in Kosovo. One of the interesting things that happened during the BOF is when a woman participant chimed in and asks India to recognize Kosovo. Immediately it triggered me and I opened the Kosovo Wikipedia page to get some understanding of the topic. Reading up on it, came to know Russia didn t agree and doesn t recognize Kosovo. Mr. Modi likes Putin and India imports a lot of its oil from Russia. Unrelatedly, but still useful, we rejected to join IPEF. Earlier, we had rejected China s BRI. India has never been as vulnerable as she is now. Our foreign balance has reached record lows. Now India has been importing quite a bit of Russian crude and has been buying arms and ammunition from them. We are also scheduled to buy a couple of warships and submarines etc. We even took arms and ammunition from them on lease. So we can t afford that they are displeased with India. Even though Russia has more than friendly relations with both China and Pakistan. At the same time, the U.S. is back to aiding Pakistan which the mainstream media in India refuses to even cover. And to top all of this, we have the Chip 4 Alliance but that needs its own article, truth be told but we will do with a paragraph Edit Addition 11th September Seems Kosovo isn t unique in that situation, there are 3-4 states like that. A brief look at worldpopulationreview tells you there are many more.

Chip 4 Alliance For almost a decade I have been screaming about this on my blog as well as everywhere that chip fabrication is a national security thing. And for years, most people deny it. And now we have chip 4 alliance. Now to understand this, you have to understand that China for almost a decade, somewhere around 2014 or so came up with something called the big fund . Now one can argue one way or the other how successful the fund has been, but it has, without doubt, created ripples so strong that the U.S., Taiwan, Japan, and probably South Korea will join and try to stem the tide. Interestingly, in this grouping, South Korea is the weakest in the statements and what they have been saying. Within the group itself, there is a lot of tension and China would use that and there are a number of unresolved issues between the three countries that both China & Russia would exploit. For e.g. the Comfort women between South Korea and Japan. Or the 1985 Accord Agreement between Japan and the U.S. Now people need to understand this, this is not just about China but also about us. If China has 5-6x times India s GDP and their research budget is at the very least 100x times what India spends, how do you think we will be self-reliant? Whom are we fooling? Are we not tired of fooling ourselves In diplomacy, countries use leverage. Sadly, we let go of some of our most experienced negotiators in 2014 and since then have been singing in the wind

Accessibility, Jitsi, IRC, Element-Desktop The Wikipedia page on Accessibility says the following Accessibility is the design of products, devices, services, vehicles, or environments so as to be usable by people with disabilities. The concept of accessible design and practice of accessible development ensures both direct access (i.e. unassisted) and indirect access meaning compatibility with a person s assistive technology. Now IRC or Internet Relay Chat has been accessible for a long time. I know of even blind people who have been able to navigate IRC quite effortlessly as there has been a lot of work done to make sure all the joints speak to each other so people with one or more disabilities still can use, and contribute without an issue. It does help that IRC and many clients have been there since the 1970s so most of them have had more than enough time to get all the bugs fixed and both text-to-speech and speech-to-text work brilliantly on IRC. Newer software like Jitsi or for that matter Telegram is lacking those features. A few days ago, discovered on Telegram I was shared that Samsung Voice input is also able to do the same. The Samsung Voice Input works wonder as it translates voice to text, I have not yet tried the text-to-speech but perhaps somebody can and they can share whatever the results can be one way or the other. I have tried element-desktop both on the desktop as well as mobile phone and it has been disappointing, to say the least. On the desktop, it is unruly and freezes once in a while, and is buggy. The mobile version is a little better but that s not saying a lot. I prefer the desktop version as I can use the full-size keyboard. The bug I reported has been there since its Riot days. I had put up a bug report even then. All in all, yesterday was disappointing

A new release 0.2.11 of RcppCCTZ is now on CRAN. RcppCCTZ uses Rcpp to bring CCTZ to R. CCTZ is a C++ library for translating between absolute and civil times using the rules of a time zone. In fact, it is two libraries. One for dealing with civil time: human-readable dates and times, and one for converting between between absolute and civil times via time zones. And while CCTZ is made by Google(rs), it is not an official Google product. The RcppCCTZ page has a few usage examples and details. This package was the first CRAN package to use CCTZ; by now four others packages include its sources too. Not ideal, but beyond our control. This version updates the include headers used in the interface API header thanks to a PR by Jing Lu, updates to upstream changes, and switched r-ci CI to r2u.

Changes in version 0.2.11 (2022-08-06)

• More specific includes in RcppCCTZ_API.h (Jing Lu in #42 closing #41).
• Synchronized with upstream CCTZ (Dirk in #43).
• Switched r-ci to r2u use.

Courtesy of my CRANberries, there is also a diffstat to the previous version. More details are at the RcppCCTZ page; code, issue tickets etc at the GitHub repository. If you like this or other open-source work I do, you can now sponsor me at GitHub.

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.