Search Results: "etbe"

7 September 2021

Russell Coker: Oracle Cloud Free Tier

It seems that every cloud service of note has a free tier nowadays and the Oracle Cloud is the latest that I ve discovered (thanks to r/homelab which I highly recommend reading). Here s Oracle s summary of what they offer for free [1]. Oracle s always free tier (where presumable always is defined as until we change our contract ) currently offers ARM64 VMs to a total capacity of 4 CPU cores, 24G of RAM, and 200G of storage with a default VM size of 1/4 that (1 CPU core and 6G of RAM). It also includes 2 AMD64 VMs that each have 1G of RAM, but a 64bit VM with 1G of RAM isn t that useful nowadays. Web Interface The first thing to note is that the management interface is a massive pain to use. When a login times out for security reasons it redirects to a web page that gives a 404 error, maybe the redirection works OK if you are using it when it times out, but if you go off and spend an hour doing something else you will return to a 404 page. A web interface should never refer you to a page with a 404. There doesn t seem to be a way of bookmarking the commonly used links (as AWS does) and the set of links on the left depend on the section you are in with no obvious way of going between sections. Sometimes I got stuck in a set of pages about authentication controls (the identity cloud ) and there seems to be no link I could click on to get me back to cloud computing, I had to go to a bookmarked link for the main cloud login page. A web interface should never force the user to type in the main URL or go to a bookmark, you should be able to navigate from every page to every other page in a logical manner. An advanced user might have their own bookmarks in their browser to suit their workflow. But a beginner should be able to go to anywhere without breaking the session. Some parts of the interface appear to be copied from AWS, but unfortunately not the good parts. The way AWS manages IP access control is not easy to manage and it s not clear why packets are dropped, Oracle copies all this. On the upside Oracle has some good Datadog style analytics so for a new deployment you can debug IP access control by seeing records of rejected packets. Just to make it extra annoying when you create a rule with multiple ports specified the web interface will expand it out to multiple rules for one port each, having ports 80 and 443 on separate lines doesn t make things easier. Also it forces you to have IPv4 and IPv6 as separate rules, so if you want HTTP and HTTPS on both IPv4 and IPv6 (a common requirement) then you need 4 separate rules. One final annoying thing is that the web interface doesn t make your previous settings a default. As I ve created many ARM images and haven t created a single AMD image it should know that the probability that I want to create an AMD image is very low and stop defaulting to that. Recovery When trying a new system you will inevitably break things and have to recover things. The way to recover from a configuration error that prevents your VM from booting and getting to a state of allowing a login is to go to stop the VM, then go to the Boot volume section under Resources and use the settings button to detach the boot volume. Then you go to another VM (which must be running), go to the Attached block volumes menu and attach it as Paravirtualised (not iSCSI and not default which will probably be iSCSI). After some time the block device will appear and you can mount it and do stuff to it. Then after umounting it you detach it from the recovery VM and attach it again to the original VM (where it will still have an entry in the Boot volume section) and boot the original VM. As an aside it s really annoying that you can t attach a volume to a VM that isn t running. My first attempt at image recovery started with making a snapshot of the Boot volume, this didn t work well because the image uses EFI and therefore GPT and because the snapshot was larger than the original block device (which incidentally was the default size). I admit that I might have made a mistake making the snapshot, but if so it shouldn t be so easy to do. With GPT if you have a larger block device then partitioning tools complain about the backup partition table not being found, and they complain even more if you try to go back to the smaller size later on. Generally GPT partition tables are a bad idea for VMs, when I run the host I don t use partition tables, I have a separate block device for each filesystem or swap space. Snapshots aren t needed for recovery, they don t seem to work very well, and if it s possible to attach a snapshot to a VM in place of it s original Boot volume I haven t figured out how to do it. Console Connection If you boot Oracle Linux a derivative of RHEL that has SE Linux enabled in enforcing mode (yay) then you can go to the Console connection . The console is a Javascript console which allows you to login on a virtual serial console on device /dev/ttyAMA0. It tells you to type help but that isn t accepted, you have a straight Linux console login prompt. If you boot Ubuntu then you don t get a working serial console, it tells you to type help for help but doesn t respond to that. It seems that the Oracle Linux kernel 5.4.17-2102.204.4.4.el7uek.aarch64 is compiled with support for /dev/ttyAMA0 (the default ARM serial device) while the kernel 5.11.0-1016-oracle compiled by Oracle for their Ubuntu VMs doesn t have it. Performance I haven t done any detailed tests of VM performance. As a quick test I used zstd to compress a 154MB file, on my home workstation (E5-2620 v4 @ 2.10GHz) it took 11.3 seconds of CPU time to compress with zstd -9 and 7.2s to decompress. On the Oracle cloud it took 7.2s and 5.4s. So it seems that for some single core operations the ARM CPU used by the Oracle cloud is about 30% to 50% faster than a E5-2620 v4 (a slightly out of date server processor that uses DDR4 RAM). If you ran all the free resources in a single VM that would make a respectable build server. If you want to contribute to free software development and only have a laptop with 4G of RAM then an ARM build/test server with 24G of RAM and 4 cores would be very useful. Ubuntu Configuration The advantage of using EFI is that you can manage the kernel from within the VM. The default Oracle kernel for Ubuntu has a lot of modules included and is compiled with a lot of security options including SE Linux. Competitors https://aws.amazon.com/free AWS offers 750 hours (just over 31 days) per month of free usage of a t2.micro or t3.micro EC2 instance (which means 1GB of RAM). But that only lasts for 12 months and it s still only 1GB of RAM. AWS has some other things that could be useful like 1 million free Lambda requests per month. If you want to run your personal web site on Lambda you shouldn t hit that limit. They also apparently have some good offers for students. https://cloud.google.com/free The Google Cloud Project (GCP) offers $300 of credit. https://cloud.google.com/free/docs/gcp-free-tier#free-tier-usage-limits GCP also has ongoing free tier usage for some services. Some of them are pretty much unlimited use (50GB of storage for Cloud Source Repositories is a heap of source code). But for VMs you get the equivalent of 1*e2-micro instance running 24*7. A e2-micro has 1G of RAM. You also only get 30G of storage and 1GB of outbound data. It s clearly not as generous an offer as Oracle, but Oracle is the underdog so they have to try harder. https://azure.microsoft.com/en-us/free/ Azure appears to be much the same as AWS, free Linux VM for a year and then other less popular services free forever (or until they change the contract). https://www.ibm.com/cloud/free The IBM cloud free tier is the least generous offer, a VM is only free for 30 days. But what they offer for 30 days is pretty decent. If you want to try the IBM cloud and see if it can do what your company needs then this will do well. If you want to have free hosting for your hobby stuff then it s no good. Oracle seems like the most generous offer if you want to do stuff, but also one of the least valuable if you want to learn things that will help you at a job interview. For job interviews AWS seems the most useful and then GCP and Azure vying for second place.

30 August 2021

Russell Coker: Links August 2021

Sciencealert has an interesting article on a game to combat misinformation by microdosing people [1]. The game seemed overly simplistic to me, but I guess I m not the target demographic. Research shows it to work. Vice has an interesting and amusing article about mass walkouts of underpaid staff in the US [2]. The way that corporations are fighting an increase in the minimum wage doesn t seem financially beneficial for them. An increase in the minimum wage means small companies have to increase salaries too and the ratio of revenue to payroll is probably worse for small companies. It seems that companies like McDonalds make oppressing their workers a higher priority than making a profit. Interesting article in Vice about how the company Shot Spotter (which determines the locations of gunshots by sound) forges evidence for US police [3]. All convictions based on Shot Spotter evidence should be declared mistrials. BitsNBites has an interesting article on the fundamental flaws of SIMD (Single Instruction Multiple Data) [4]. The Daily Dot has a disturbing article anbout the possible future of the QAnon movement [5]. Let s hope they become too busy fighting each other to hurt many innocent people. Ben Taylor wrote an interesting blog post suggesting that Web Assembly should be a default binary target [6]. I don t support that idea but I think that considering it is useful. Web assembly could be used more for non-web things and it would be a better option than Node.js for some things. There are also some interesting corner cases like games, Minecraft was written in Java and there s no reason that Web Assembly couldn t do the same things. Vice has an interesting article about the Phantom encrypted phone service that ran on Blackberry handsets [7]. Australia really needs legislation based on the US RICO law! Vice has an interesting article about an encrypted phone company run by drug dealers [8]. Apparently after making an encrypted phone system for their own use they decided to sell it to others and made millions of dollars. They could have run a successful legal business. Salon has an insightful interview with Michael Petersen about his research on fake news and people who share it because they need chaos [9]. Apparently low status people who are status seeking are a main contributor to this, they share fake news knowingly to spread chaos. A society with less inequality would have less problems with fake news. Salon has another insightful interview with Michael Petersen, about is later research on fake news as an evolutionary strategy [10]. People knowingly share fake news to mobilise their supporters and to signal allegiance to their group. The more bizarre the beliefs are the more strongly they signal allegiance. If an opposing group has a belief then they can show support for their group by having the opposite belief (EG by opposing vaccination if the other political side supports doctors). He also suggests that lying can be a way of establishing dominance, the more honest people are opposed by a lie the more dominant the liar may seem. Vice has an amusing article about how police took over the Encrochat encrypted phone network that was mostly used by criminals [11]. It s amusing to read of criminals getting taken down like this. It s also interesting to note that the authorities messed up by breaking the wipe facility which alerted the criminals that their security was compromised. The investigation could have continued for longer if they hadn t changed the functionality of compromised phones. A later vice article mentioned that the malware installed on Encrochat devices recorded MAC addresses of Wifi access points which was used to locate the phones even though they had the GPS hardware removed. Cory Doctorow wrote an insightful article for Locus about the insufficient necessity of interoperability [12]. The problem if monopolies is not just an inability to interoperate with other services or leave it s losing control over your life. A few cartel participants interoperating will be able to do all the bad things to us tha a single monopolist could do.

31 July 2021

Russell Coker: Links July 2021

The News Tribune published an article in 2004 about the Dove of Oneness , a mentally ill woman who got thousands of people to believe her crazy ideas about NESARA [1]. In recent time the QANON conspiracy theory has drawn on the NESARA cult and encouraged it s believers to borrow money and spend it in the belief that all debts will be forgiven (something which was not part of NESARA). The Wikipedia page about NESARA (proposed US legislation that was never considered by the US congress) notes that the second edition of the book about it was titled Draining the Swamp: The NESARA Story Monetary and Fiscal Policy Reform . It seems like the Trump cult has been following that for a long time. David Brin (best-selling SciFi Author and NASA consultant) wrote an insightful blog post about the Tytler Calumny [2], which is the false claim that democracy inevitably fails because poor people vote themselves money. When really the failure is of corrupt rich people subverting the government processes to enrich themselves at the expense of their country. It s worth reading, and his entire blog is also worth reading. Cory Doctorow has an insightful article about his own battle with tobacco addiction and the methods that tobacco companies and other horrible organisations use to prevent honest discussion about legislation [3]. Cory Doctorow has an insightful article about consent theater which is describes how consent in most agreements between corporations and people is a fraud [4]. The new GDPR sounds good. The forum for the War Thunder game had a discussion on the accuracy of the Challenger 2 tank which ended up with a man who claims to be a UK tank commander posting part of a classified repair manual [5]. That s pretty amusing, and also good advertising for War Thunder. After reading about this I discovered that it s free on Steam and runs on Linux! Unfortunately it whinged about my video drivers and refused to run. Corey Doctorow has an insightful and well researched article about the way the housing market works in the US [6]. For house prices to increase conditions for renters need to be worse, that may work for home owners in the short term but then in the long term their children and grandchildren will end up renting.

16 July 2021

Russell Coker: Thoughts about RAM and Storage Changes

My first Linux system in 1992 was a 386 with 4MB of RAM and a 120MB hard drive which (for some reason I forgot) only was supported by Linux for about 90MB. My first hard drive was 70MB and could do 500KB/s for contiguous IO, my first Linux hard drive was probably a bit faster, maybe 1MB/s. My current Linux workstation has 64G of RAM and 2*1TB NVMe devices that can sustain about 1.1GB/s. The laptop I m using right now has 8GB of RAM and a 180GB SSD that can do 380MB/s. My laptop has 2000* the RAM of my first Linux system and maybe 400* the contiguous IO speed. Currently I don t even run a VM with less than 4GB of RAM, NB I m not saying that smaller VMs aren t useful merely that I don t happen to be using them now. Modern AMD64 CPUs support 2MB huge pages . As a proportion of system RAM if I used 2MB pages everywhere they would be a smaller portion of system RAM than the 4KB pages on my first Linux system! I am not suggesting using 2MB pages for general systems. For my workstations the majority of processes are using less than 10MB of resident memory and given the different uses for memory mapped shared objects, memory mapped file IO, malloc(), stack, heap, etc there would be a lot of inefficiency having 2MB the limit for all allocation. But as systems worked with 4MB of RAM or less and 4K pages it would surely work to have only 2MB pages with 64GB or more of RAM. Back in the 90s it seemed ridiculous to me to have 256 byte pages on a 68030 CPU, but 4K pages on a modern AMD64 system is even more ridiculous. Apparently AMD64 supports 1GB pages on some CPUs, that seems ridiculously large but when run on a system with 1TB of RAM that s comparable to 4K pages on my first Linux system. Currently AWS offers 24TB EC2 instances and the Google Cloud Project offers 12TB virtual machines. It might even make sense to have the entire OS using 1GB pages for some usage scenarios on such systems, wasting tens of GB of RAM to save TLB thrashing might be a good trade-off. My personal laptop has 200* the RAM of my first Linux system and maybe 400* the contiguous IO speed. An employer recently assigned me a Thinkpad Carbon X1 Gen6 with an NVMe device that could sustain 5GB/s until the CPU overheated, that s 5000* the contiguous IO speed of my first Linux hard drive. My Linux hard drive had a 28ms average access time and my first Linux hard drive probably was a little better, let s call it 20ms for the sake of discussion. It s generally quoted that access times for NVMe are at best 10us, that s 2000* better than my first Linux hard drive. As seek times are the main factor for swap performance a laptop with 8GB of RAM and a fast NVMe device could be expected to give adequate performance with 2000* the swap of my first Linux system. For the work laptop in question I had 8G of swap and my personal laptop has 6G of swap which is somewhat comparable to the 4MB of swap on my first Linux system in that swap is about equal to RAM size, so I guess my personal laptop is performing better than it can be expected to. These are just some idle thoughts about hardware changes over the years. Don t take it as advice for purchasing hardware and don t take it too seriously in general. Also when writing comments don t restrict yourself to being overly serious, feel free to run the numbers on what systems with petabytes of Optane might be like, speculate on what NUMA systems in laptops might be like, etc. Go wild.

5 July 2021

Russell Coker: Servers and Lockdown

OS security features and server class systems are things that surely belong together. If a program is important enough to buy expensive servers to run it then it s important enough that you want to have all the OS security features enabled. For such an important program you will also want to have all possible monitoring systems running so you can predict hardware failures etc. Therefore you would expect that you could buy a server, setup the vendor s management software, configure your Linux kernel with security features such as lockdown (a LSM that restricts access to /dev/mem, the iopl() system call, and other dangerous things [1]), and have it run nicely! You will be disappointed if you try doing that on a HP or Dell server though. HP Problems
[370742.622525] Lockdown: hpasmlited: raw io port access is restricted; see man kernel_lockdown.7
The above message is logged when trying to INSTALL (not even run) the hp-health package from the official HP repository (as documented in my previous blog post about the HP ML-110 Gen9 [2]) with lockdown=integrity (the less restrictive lockdown option). Now the HP package in question is in their repository for Debian/Stretch (released in 2017) and the Lockdown LSM was documented by LWN as being released in 2019, so not supporting a Debian/Bullseye feature in Debian/Stretch packages isn t inherently a bad thing apart from the fact that they haven t released a new version of that package since. The Stretch package that I am testing now was released in 2019. Also it s been regarded as best practice to have device drivers for this sort of thing since long before 2017.
# hplog -v
ERROR: Could not open /dev/cpqhealth/cdt.
Please make sure the Health Monitor is started.
Attempting to run the hplog -v command (to view the HP hardware log) gives the above error. Strace reveals that it could and did open /dev/cpqhealth/cdt but had problems talking to something (presumably the Health Monitor daemon) over a Unix domain socket. It would be nice if they could at least get the error message right! Dell Problems
[   13.811165] Lockdown: smbios-sys-info: /dev/mem,kmem,port is restricted; see man kernel_lockdown.7
[   13.820935] Lockdown: smbios-sys-info: raw io port access is restricted; see man kernel_lockdown.7
[   18.118118] Lockdown: dchcfg: raw io port access is restricted; see man kernel_lockdown.7
[   18.127621] Lockdown: dchcfg: /dev/mem,kmem,port is restricted; see man kernel_lockdown.7
[   19.371391] Lockdown: dsm_sa_datamgrd: raw io port access is restricted; see man kernel_lockdown.7
[   19.382147] Lockdown: dsm_sa_datamgrd: /dev/mem,kmem,port is restricted; see man kernel_lockdown.7
Above is a sample of the messages when booting a Dell PowerEdge R710 with lockdown=integrity with the srvadmin-omacore package installed from the official Dell repository I describe in my blog post about the Dell PowerEdge R710 [3]. Now that repository is for Ubuntu/Xenial which was released in 2015, but again it was best practice to have device drivers for this many years ago. Also the newest Debian based releases that Dell apparently supports are Ubuntu/Xenial and Debian/Jessie which were both released in 2015.
# omreport system esmlog
Error! No Embedded System Management (ESM) log found on this system.
Above is the result when I try to view the ESM log (the Dell hardware log). How Long Should Server Support Last? The Wikipedia List of Dell PowerEdge Servers shows that the R710 is a Generation 11 system. Generation 11 was first released in 2010 and Generation 12 was first released in 2012. Generation 13 was the latest hardware Dell sold in 2015 when they apparently ceased providing newer OS support for Generation 11. Dell currently sells Generation 15 systems and provides more recent support for Generation 14 and Generation 15. I think it s reasonable to debate whether Dell should support servers for 4 generations. But given that a major selling point of server class systems is that they have long term support I think it would make sense to give better support for this and not drop support when it s only 2 versions from the latest release! The support for Dell Generation 11 hardware only seems to have lasted for 3 years after Generation 12 was first released. Also it appears that software support for Dell Generation 13 ceased before Generation 14 was released, that sucks for the people who bought Generation 13 when they were new! HP is currently selling Gen 10 servers which were first released at the end of 2017. So it appears that HP stopped properly supporting Gen 9 servers as soon as Gen 10 servers were released! One thing to note about these support times, when the new generation of hardware was officially released the previous generation was still on sale. So while HP Gen 10 servers officially came out in 2017 that doesn t necessarily mean that someone who wanted to buy a ML-110 Gen10 could actually have done so. For comparison Red Hat Enterprise Linux has been supported for 4-6 years for every release they made since 2005 and Ubuntu has always had a 5 year LTS support for servers. How To Do It Properly The correct way of interfacing with hardware is via a device driver that is supported in the kernel.org tree. That means it goes through the usual kernel source code quality checks which are really good at finding bugs and gives users an assurance that the code won t cause security problems. Generally nothing about the code from Dell or HP gives me confidence that it should be directly accessing /dev/kmem or raw IO ports without risk of problems. Once a driver is in the kernel.org tree it will usually stay there forever and not require further effort from the people who submit it. Then it just works for everyone and tends to work with any other kernel features that people use, like LSMs. If they released the source code to the management programs then it would save them even more effort as they could be maintained by the community.

30 June 2021

Russell Coker: Links June 2021

MIT Technology Review has an interesting article about Google Project Zero shutting down a western intelligence operation [1]. There s an Internet trend of people eating rotten meat they call high meat (rotten meat) [2]. This is up there with people setting themselves on fire and nut shot videos. A young female who was making popular Twitter posts about motorbikes turned out to be a 50yo man using deep fake technology [3]. He has long hair IRL and just needed to replace his face. After coming out of the closet he has continued making such videos and remains popular. FYHTECH has an informative blog post about using sgdisk to backup and restore GPT partition tables [4]. This is in the Debian package gdisk along with several other tools for managing partition tables. One interesting thing to note is that you can backup a partition table and restore to a smaller device (with a bunch of warnings that you can ignore if you know what you are doing). This is the only way I ve discovered to cleanly truncate a GPT partitioned disk, which is sometimes necessary when running VMs. Insightful blog post about PCIe bifurcation and how PCIe lanes are assigned to sockets [5]. This explains why many motherboards have sockets with unused PCIe lanes, EG *8 sockets that are wired for *4. The PCIe slots all go back to the CPU which has a limited number of *16 PCIe connections that are bifurcated to make the larger number of PCIe slots on the motherboard. New Republic has an interesting article on the infamous transphobe Jordan Peterson s battle with tranquiliser dependency [6]. Wired has an interesting article about the hack of RSA infrastructure related to the SecureID keys 10 years ago [7]. Apparently some 10 year NDAs had delayed it. There are many posts about the situation with Freenode, I think that this one best captures the problems in the shortest amount of text [8]. You could spend a few hours reading about it as I have just done, but just reading this gives you the basics that you need to know to avoid Freenode. That blog post has links to articles about Andrew Lee s involvement with Mt Gox and claims to be the heir to the throne of Korea (which is not a monarchy). Nicholas Wade wrote an insightful and informative article about the origin of Covid19, which leads to the conclusion that it was made in a Chinese laboratory [9]. I first saw this in David Brin s Facebook feed. I would be hesitant to share this sort of thing if it wasn t reviewed by a reliable source, I think David Brin has the skill to analyse this sort of article and the contacts to allow him to seek verification of any scientific issues that are outside his field. I believe that this article is reliable and it s conclusion is most likely to be correct. Interesting Wired article about an art project using display computers at Apple stores to photograph people [10]. Ends with a visit from the FBI.

7 June 2021

Russell Coker: Dell PowerEdge T320 and Linux

I recently bought a couple of PowerEdge T320 servers, so now to learn about setting them up. They are a little newer than the R710 I recently setup (which had iDRAC version 6), they have iDRAC version 7. RAM Speed One system has a E5-2440 CPU with 2*16G DDR3 DIMMs and a Memtest86+ speed of 13,043MB/s, the other is essentially identical but with a E5-2430 CPU and 4*16G DDR3 DIMMs and a Memtest86+ speed of 8,270MB/s. I had expected that more DIMMs means better RAM performance but this isn t what happened. I firstly upgraded the BIOS, as I expected it didn t make a difference but it s a good thing to try first. On the E5-2430 I tried removing a DIMM after it was pointed out on Facebook that the CPU has 3 memory channels (here s a link to a great site with information on that CPU and many others [1]). When I did that I was prompted to disable advanced ECC (which treats pairs of DIMMs as a single unit for ECC allowing correcting more than 1 bit errors) and I had to move the 3 remaining DIMMS to different slots. That improved the performance to 13,497MB/s. I then put the spare DIMM into the E5-2440 system and the performance increased to 13,793MB/s, when I installed 4 DIMMs in the E5-2440 system the performance remained at 13,793MB/s and the E5-2430 went down to 12,643MB/s. This is a good result for me, I now have the most RAM and fastest RAM configuration in the system with the fastest CPU. I ll sell the other one to someone who doesn t need so much RAM or performance (it will be really good for a small office mail server and NAS). Firmware Update BIOS The first issue is updating the BIOS, unfortunately the first link I found to the Dell web site didn t have a link to download the Linux installer. It offered a Windows binary, an EFI program, and a DOS binary. I m not about to install Windows if there is any other option and EFI is somewhat annoying, so that leaves DOS. The first Google result for installing FreeDOS advised using unetbootin , that didn t work at all for me (created a USB image that the Dell BIOS didn t recognise as bootable) and even if it did it wouldn t have been a good solution. I went to the FreeDOS download page [2] and got the Lite USB zip file. That contained FD12LITE.img which I could just dd to a USB stick. I then used fdisk to create a second 32MB partition, used mkfs.fat to format it, and then copied the BIOS image file to it. I booted the USB stick and then ran the BIOS update program from drive D:. After the BIOS update this became the first system I ve seen get a totally green result from spectre-meltdown-checker ! I found the link to the Linux installer for the new Dell BIOS afterwards, but it was still good to play with FreeDOS. PERC Driver I probably didn t really need to update the PERC (PowerEdge Raid Controller) firmware as I m just going to run it in JBOD mode. But it was easy to do, a simple bash shell script to update it. Here are the perccli commands needed to access disks, it s all hot-plug so you can insert disks and do all this without a reboot:
# show overview
perccli show
# show controller 0 details
perccli /c0 show all
# show controller 0 info with less detail
perccli /c0 show
# clear all "foreign" RAID members
perccli /c0 /fall delete
# add a vd (RAID) of level RAID0 (r0) with the drive 32:0 (enclosure:slot from above command)
perccli /c0 add vd r0 drives=32:0
The perccli /c0 show command gives the following summary of disk ( PD in perccli terminology) information amongst other information. The EID is the enclosure, Slt is the slot (IE the bay you plug the disk into) and the DID is the disk identifier (not sure what happens if you have multiple enclosures). The allocation of device names (sda, sdb, etc) will be in order of EID:Slt or DID at boot time, and any drives added at run time will get the next letters available.
----------------------------------------------------------------------------------
EID:Slt DID State DG       Size Intf Med SED PI SeSz Model                     Sp 
----------------------------------------------------------------------------------
32:0      0 Onln   0  465.25 GB SATA SSD Y   N  512B Samsung SSD 850 EVO 500GB U  
32:1      1 Onln   1  465.25 GB SATA SSD Y   N  512B Samsung SSD 850 EVO 500GB U  
32:3      3 Onln   2   3.637 TB SATA HDD N   N  512B ST4000DM000-1F2168        U  
32:4      4 Onln   3   3.637 TB SATA HDD N   N  512B WDC WD40EURX-64WRWY0      U  
32:5      5 Onln   5 278.875 GB SAS  HDD Y   N  512B ST300MM0026               U  
32:6      6 Onln   6 558.375 GB SAS  HDD N   N  512B AL13SXL600N               U  
32:7      7 Onln   4   3.637 TB SATA HDD N   N  512B ST4000DM000-1F2168        U  
----------------------------------------------------------------------------------
The PERC controller is a MegaRAID with possibly some minor changes, there are reports of Linux MegaRAID management utilities working on it for similar functionality to perccli. The version of MegaRAID utilities I tried didn t work on my PERC hardware. The smartctl utility works on those disks if you tell it you have a MegaRAID controller (so obviously there s enough similarity that some MegaRAID utilities will work). Here are example smartctl commands for the first and last disks on my system. Note that the disk device node doesn t matter as all device nodes associated with the PERC/MegaRAID are equal for smartctl.
# get model number etc on DID 0 (Samsung SSD)
smartctl -d megaraid,0 -i /dev/sda
# get all the basic information on DID 0
smartctl -d megaraid,0 -a /dev/sda
# get model number etc on DID 7 (Seagate 4TB disk)
smartctl -d megaraid,7 -i /dev/sda
# exactly the same output as the previous command
smartctl -d megaraid,7 -i /dev/sdc
I have uploaded etbemon version 1.3.5-6 to Debian which has support for monitoring smartctl status of MegaRAID devices and NVMe devices. IDRAC To update IDRAC on Linux there s a bash script with the firmware in the same file (binary stuff at the end of a shell script). To make things a little more exciting the script insists that rpm be available (running apt install rpm fixes that for a Debian system). It also creates and runs other shell scripts which start with #!/bin/sh but depend on bash syntax. So I had to make /bin/sh a symlink to /bin/bash. You know you need this if you see errors like typeset: not found and [: -eq: unexpected operator and then the system reboots. Dell people, please test your scripts on dash (the Debian /bin/sh) or just specify #!/bin/bash. If the IDRAC update works it will take about 8 minutes. Lifecycle Controller The Lifecycle Controller is apparently for installing OS and firmware updates. I use Linux tools to update Linux and I generally don t plan to update the firmware after deployment (although I could do so from Linux if needed). So it doesn t seem to offer anything useful to me. Setting Up IDRAC For extra excitement I decided to try to setup IDRAC from the Linux command-line. To install the RAC setup tool you run apt install srvadmin-idracadm7 libargtable2-0 (because srvadmin-idracadm7 doesn t have the right dependencies).
# srvadmin-idracadm7 is missing a dependency
apt install srvadmin-idracadm7 libargtable2-0
# set the IP address, netmask, and gatewat for IDRAC
idracadm7 setniccfg -s 192.168.0.2 255.255.255.0 192.168.0.1
# put my name on the front panel LCD
idracadm7 set System.LCD.UserDefinedString "Russell Coker"
Conclusion This is a very nice deskside workstation/server. It s extremely quiet with hardly any fan noise and the case is strong enough to contain the noise of hard drives. When running with 3* 3.5 SATA disks and 2*10k 2.5 SAS disks on a wooden floor it wasn t annoyingly loud. Without the SAS disks it was as quiet as you can expect any PC to be, definitely not the volume you expect from a serious server! I bought the T320 systems loaded with SAS disks which made them quite loud, I immediately put the disks on ebay and installed SATA SSDs and hard drives which gives me more performance and more space than the SAS disks with less cost and almost no noise. 8*3.5 drive bays gives room for expansion. I currently have 2*SATA SSDs and 3*SATA disks, the SSDs are for the root filesystem (including /home) and the disks are for a separate filesystem for large files.

6 June 2021

Russell Coker: Netflix and IPv6

It seems that Netflix has an ongoing issue of not working well with IPv6, apparently they have some sort of region checking code that doesn t correctly identify IPv6 prefixes. To fix this I wrote the following script to make a small zone file with only A records for Netflix and no AAAA records. The $OUT.header file just has the SOA record for my fake netflix.com domain.
#!/bin/bash
OUT=/etc/bind/data/netflix.com
HEAD=$OUT.header
cp $HEAD $OUT
dig -t a www.netflix.com @8.8.8.8 sed -n -e "s/^.*IN/www IN/p" grep [0-9]$ >> $OUT
dig -t a android.prod.cloud.netflix.com @8.8.8.8 sed -n -e "s/^.*IN/android.prod.cloud IN/p" grep [0-9]$ >> $OUT
/usr/sbin/rndc reload > /dev/null
Update I updated this post to add a line for android.prod.cloud.netflix.com which is the address used by Android devices.

1 June 2021

Russell Coker: Internode NBN with Arris CM8200 on Debian

I ve recently signed up for Internode NBN while using the Arris CM8200 device supplied by Optus (previously used for a regular phone service). I took the configuration mostly from Dean s great blog post on the topic [1]. One thing I changed was the /etc/networ/interfaces configuration, I used the following:
# VLAN ID 2 for Internode's NBN HFC.
auto eth1.2
iface eth1.2 inet manual
  vlan-raw-device eth1
auto nbn
iface nbn inet ppp
    pre-up /bin/ip link set eth1.2 up
    provider nbn
There is no need to have a section for eth1 when you have a section for eth1.2. IPv6 IPv6 for only one system With a line in /etc/ppp/options containing only ipv6 , you get an IPv6 address automatically for the ppp0 interface after starting pppd. IPv6 for your lan Internode has documented how to configure the WIDE DHCPv6 client to get an IPv6 prefix (subnet) [2]. Just install the wide-dhcpv6-client package and put your interface names in a copy of the Internode example config and that works. That gets you a /64 assigned to your local Ethernet. Here s an example of /etc/wide-dhcpv6/dhcp6c.conf:
interface ppp0  
    send ia-pd 0;
    script "/etc/wide-dhcpv6/dhcp6c-script";
 ;
id-assoc pd  
    prefix-interface br0  
        sla-id 0;
        sla-len 8;
     ;
 ;
For providing addresses to other systems on your LAN they recommend radvd version 1.1 or greater, Debian/Bullseye will ship with version 2.18. Here is an example /etc/radvd.conf that will work with it. It seems that you have to manually (or with a script) set the value to use in place of xxxx:xxxx:xxxx:xxxx from the value that is assigned to eth0 (or whichever interface you are using) by the wide-dhcpv6-client.
interface eth0   
        AdvSendAdvert on;
        MinRtrAdvInterval 3; 
        MaxRtrAdvInterval 10;
        prefix xxxx:xxxx:xxxx:xxxx::/64   
                AdvOnLink on; 
                AdvAutonomous on; 
                AdvRouterAddr on; 
         ;
 ;
Either the configuration of the wide dhcp client or radvd removes the default route from ppp0, so you need to run a command like
ip -6 route add default dev ppp0 to put it back. Probably having ipv6 , is the wrong thing to do when using wide-dhcp-client and radvd. On a client machine with bridging I needed to have net.ipv6.conf.br0.accept_ra=2 in /etc/sysctl.conf to allow it to accept route advisory messages on the interface (in this case eth0), for machines without bridging I didn t need that. Firewalling The default model for firewalling nowadays seems to be using NAT and only configuring specific ports to be forwarded to machines on the LAN. With IPv6 on the LAN every system can directly communicate with the rest of the world which may be a bad thing. The following lines in a firewall script will drop all inbound packets that aren t in response to packets that are sent out. This will give an equivalent result to the NAT firewall people are used to and you can always add more rules to allow specific ports in.
ip6tables -A FORWARD -i ppp+ -m state --state ESTABLISHED,RELATED -j ACCEPT
ip6tables -A FORWARD -i ppp+ -i DROP

31 May 2021

Russell Coker: Some Ideas About Storage Reliability

Hard Drive Brands When people ask for advice about what storage to use they often get answers like use brand X, it works well for me and brand Y had a heap of returns a few years ago . I m not convinced there is any difference between the small number of manufacturers that are still in business. One problem we face with reliability of computer systems is that the rate of change is significant, so every year there will be new technological developments to improve things and every company will take advantage of them. Storage devices are unique among computer parts for their requirement for long-term reliability. For most other parts in a computer system a fault that involves total failure is usually easy to fix and even a fault that causes unreliable operation usually won t spread it s damage too far before being noticed (except in corner cases like RAM corruption causing corrupted data on disk). Every year each manufacturer will bring out newer disks that are bigger, cheaper, faster, or all three. Those disks will be expected to remain in service for 3 years in most cases, and for consumer disks often 5 years or more. The manufacturers can t test the new storage technology for even 3 years before releasing it so their ability to prove the reliability is limited. Maybe you could buy some 8TB disks now that were manufactured to the same design as used 3 years ago, but if you buy 12TB consumer grade disks, the 20TB+ data center disks, or any other device that is pushing the limits of new technology then you know that the manufacturer never tested it running for as long as you plan to run it. Generally the engineering is done well and they don t have many problems in the field. Sometimes a new range of disks has a significant number of defects, but that doesn t mean the next series of disks from the same manufacturer will have problems. The issues with SSDs are similar to the issues with hard drives but a little different. I m not sure how much of the improvements in SSDs recently have been due to new technology and how much is due to new manufacturing processes. I had a bad experience with a nameless brand SSD a couple of years ago and now stick to the better known brands. So for SSDs I don t expect a great quality difference between devices that have the names of major computer companies on them, but stuff that comes from China with the name of the discount web store stamped on it is always a risk. Hard Drive vs SSD A few years ago some people were still avoiding SSDs due to the perceived risk of new technology. The first problem with this is that hard drives have lots of new technology in them. The next issue is that hard drives often have some sort of flash storage built in, presumably a SSHD or Hybrid Drive gets all the potential failures of hard drives and SSDs. One theoretical issue with SSDs is that filesystems have been (in theory at least) designed to cope with hard drive failure modes not SSD failure modes. The problem with that theory is that most filesystems don t cope with data corruption at all. If you want to avoid losing data when a disk returns bad data and claims it to be good then you need to use ZFS, BTRFS, the NetApp WAFL filesystem, Microsoft ReFS (with the optional file data checksum feature enabled), or Hammer2 (which wasn t production ready last time I tested it). Some people are concerned that their filesystem won t support wear levelling for SSD use. When a flash storage device is exposed to the OS via a block interface like SATA there isn t much possibility of wear levelling. If flash storage exposes that level of hardware detail to the OS then you need a filesystem like JFFS2 to use it. I believe that most SSDs have something like JFFS2 inside the firmware and use it to expose what looks like a regular block device. Another common concern about SSD is that it will wear out from too many writes. Lots of people are using SSD for the ZIL (ZFS Intent Log) on the ZFS filesystem, that means that SSD devices become the write bottleneck for the system and in some cases are run that way 24*7. If there was a problem with SSDs wearing out I expect that ZFS users would be complaining about it. Back in 2014 I wrote a blog post about whether swap would break SSD [1] (conclusion it won t). Apart from the nameless brand SSD I mentioned previously all of my SSDs in question are still in service. I have recently had a single Samsung 500G SSD give me 25 read errors (which BTRFS recovered from the other Samsung SSD in the RAID-1), I have yet to determine if this is an ongoing issue with the SSD in question or a transient thing. I also had a 256G SSD in a Hetzner DC give 23 read errors a few months after it gave a SMART alert about Wear_Leveling_Count (old age). Hard drives have moving parts and are therefore inherently more susceptible to vibration than SSDs, they are also more likely to cause vibration related problems in other disks. I will probably write a future blog post about disks that work in small arrays but not in big arrays. My personal experience is that SSDs are at least as reliable as hard drives even when run in situations where vibration and heat aren t issues. Vibration or a warm environment can cause data loss from hard drives in situations where SSDs will work reliably. NVMe I think that NVMe isn t very different from other SSDs in terms of the actual storage. But the different interface gives some interesting possibilities for data loss. OS, filesystem, and motherboard bugs are all potential causes of data loss when using a newer technology. Future Technology The latest thing for high end servers is Optane Persistent memory [2] also known as DCPMM. This is NVRAM that fits in a regular DDR4 DIMM socket that gives performance somewhere between NVMe and RAM and capacity similar to NVMe. One of the ways of using this is Memory Mode where the DCPMM is seen by the OS as RAM and the actual RAM caches the DCPMM (essentially this is swap space at the hardware level), this could make multiple terabytes of RAM not ridiculously expensive. Another way of using it is App Direct Mode where the DCPMM can either be a simulated block device for regular filesystems or a byte addressable device for application use. The final option is Mixed Memory Mode which has some DCPMM in Memory Mode and some in App Direct Mode . This has much potential for use of backups and to make things extra exciting App Direct Mode has RAID-0 but no other form of RAID. Conclusion I think that the best things to do for storage reliability are to have ECC RAM to avoid corruption before the data gets written, use reasonable quality hardware (buy stuff with a brand that someone will want to protect), and avoid new technology. New hardware and new software needed to talk to new hardware interfaces will have bugs and sometimes those bugs will lose data. Filesystems like BTRFS and ZFS are needed to cope with storage devices returning bad data and claiming it to be good, this is a very common failure mode. Backups are a good thing.

30 May 2021

Russell Coker: Wifi Performance on Linux

Wifi usually just works. In the past I haven t had to worry much about performance as for home use things have always been bearable and at work it s never been my job so I just file a bug report with the relevant people when things go wrong. But a few years ago I had some problems. For my home network I got a free Wifi AP which wasn t performing well. My AP supported 802.11 modes b/g or g/n (b, g, and n are slow, medium, and fast speeds). I initially had the AP running in b/g mode because I had an 802.11b USB wifi device that I used. When I replaced that with one that did 802.11g I tried changing the AP to g/n mode but performance was even worse on my laptop (although quite good on phones) so I switched back. For phones it appeared to work well giving 54Mb/s while on my laptop (a second hand Thinkpad X1 Carbon) it was giving 11Mb/s at best and often much less than that. The best demonstration of problems was to start transferring a large file while pinging a system on the LAN the AP was connected to. Usually it would give ping times of 1s or more, sometimes 5s+ ping times. While this was happening the Invalid misc count increased rapidly, often by more than 100 per second. The results of Google searches suggest that Invalid misc is due to interference and recommend changing the channel. My AP had been on channel 1 which had performed poorly, channels 2-8 were ok, and channel 9 seemed reasonably good. As an aside trying all channels manually is not a good idea, it takes a lot of time and gives little useful data. After changing to channel 9 it still only gave about 500KB/s when transferring large files with ping times of about 100ms, but that s a big improvement. I tried running iwlist scanning to scan the Wifi network for other APs, that showed that channel 1 was used a lot but didn t make it clear what I should do other than that. The next thing I tried was the Wifi Analyser app on Android [1] (which doesn t work on my latest phone, I don t know if it s still being actively maintained, it will definitely work on older phones). That has a nice graph mode that shows which channels are used and how the frequencies spread and interfere with other channels. One thing I hadn t realised before I looked at the graphs is that 802.11n uses 4 channels and interferes past that. If you have two 802.11n devices you don t have much space left out of the 14 channels available. To make more space I configured the Wifi AP in my ADSL modem to 802.11b/g mode and assigned it a channel away from the others making 4 channels available with no interference. After that iwconfig reported between 60 and 120Mb/s and I got consistent transfer rates over 1.5MB/s while ping times remained below 100ms. The 5GHz frequency range is less congested. But at the time I didn t feel like buying 5GHz equipment. Since that time I had signed up with an ISP that had a good deal on a Wifi AP that had 5GHz. Now I have all my devices configured to use 5GHz or 2.4GHz depending on which they think is best. So there s less devices on 2.4GHz and the AP is configured for 20MHz channel width in the 2.4GHz range (which means 802.11b/g). Conclusion 802.11n seems to be a bad idea unless you run the only AP in an area. In a suburban area you will have 3 other houses broadcasting in your area and 802.11n is bad for everyone. The worst case scenario would be one person using 802.11n and interfering with everyone else s 802.11g and then having everyone else turn on 802.11n to try and make things faster. 5GHz is less congested as most people run old hardware. It also has a shorter range which has the upside of getting less interference from other people. I m considering installing 5GHz APs at both ends of my house and configuring all my new devices to not use 2.4GHz. Wifi spectrum analysis software is much better than manual testing of channels or trying to deduce things from the output if iwlist scanning .

Russell Coker: USB Cables and Cameras

This page has summaries of some USB limits [1]. USB 2.0 has the longest cable segment limit of 5M (1.x, 3.x, and USB-C are all shorter), so USB 2.0 is what you want for long runs. The USB limit for daisy chained devices is 7 (including host and device), so that means a maximum of 5 hubs or a total distance between PC and device of 30M. There are lots of other ways of getting longer distances, the cheapest seems to be putting an old PC at the far end of an Ethernet cable. Some (many? most?) laptops have USB for the interface to the built in camera, and these are sold from scrapped laptops. You could probably setup a home monitoring system in a typical home by having a centrally located PC with USB hubs fanning out to the corners. But old Android phones on a Wifi network seems like an easier option if you can prevent the phones from crashing all the time.

Russell Coker: HP ML110 Gen9

I ve just bought a HP ML110 Gen9 as a personal workstation, here are my notes about it and documentation on running Debian on it. Why a Server? I bought this is because the ML350p Gen8 turned out to be too noisy for my taste [1]. I ve just been editing my page about Memtest86+ RAM speeds [2], over the course of 10 years (high end laptop in 2001 to low end server in 2011) RAM speed increased by a factor of 100. RAM speed has been increasing at a lower rate than CPU speed and is becoming an increasing bottleneck on system performance. So while I could get a faster white-box system the cost of a second-hand server isn t that great and I m getting a system that s 100* faster than what was adequate for most tasks in 2001. HP makes some nice workstation class machines with ECC RAM (think server without remote management, hot-swap disks, or redundant PSU but with sound hardware). But they are significantly more expensive on the second hand market than servers. This server cost me $650 and came with 2*480G DC grade SSDs (Intel but with HPE stickers). I hope that more than half of the purchase price will be recovered from selling the SSDs (I will use NVMe). Also 64G of non-ECC RAM costs $370 from my local store. As I want lots of RAM for testing software on VMs it will probably turn out that the server cost me less than the cost of new RAM once I ve sold the SSDs! Monitoring
wget -O /usr/local/hpePublicKey2048_key1.pub https://downloads.linux.hpe.com/SDR/hpePublicKey2048_key1.pub
echo "# HP monitoring" >> /etc/apt/sources.list
echo "deb [signed-by=/usr/local/hpePublicKey2048_key1.pub] http://downloads.linux.hpe.com/SDR/downloads/MCP/Debian/ stretch/current-gen9 non-free" >> /etc/apt/sources.list
The above commands will make the management utilities installable on Debian/Buster. If using Bullseye (Testing at the moment) then you need to have Buster repositories in APT for dependencies, HP doesn t seem to have packaged all their utilities for Buster.
wget -r -np -A Contents-amd64.bz2 http://downloads.linux.hpe.com/SDR/repo/mcp/debian/dists
To find out which repositories had the programs I need I ran the above recursive wget and then uncompressed them for grep -R (as an aside it would be nice if bzgrep supported -R). I installed the hp-health package which has hpasmcli for viewing and setting many configuration options and hplog for viewing event log data and thermal data (among a few other things). I ve added a new monitor to etbemon hp-temp.monitor to monitor HP server temperatures, I haven t made a configuration option to change the thresholds for what is considered normal because I don t expect server class systems to be routinely running above the warning temperature. For the linux-temp.monitor script I added a command-line option for the percentage of the high temperature that is an error condition as well as an option for the number of CPU cores that need to be over-temperature, having one core permanently over the high temperature due to a web browser seems standard for white-box workstations nowadays. The hp-health package depends on libc6-i686 lib32gcc1 even though none of the programs it contains use lib32gcc1. Depending on lib32gcc1 instead of lib32gcc1 lib32gcc-s1 means that installing hp-health requires removing mesa-opencl-icd which probably means that BOINC can t use the GPU among other things. I solved this by editing /var/lib/dpkg/status and changing the package dependencies to what I desired. Note that this is not something for a novice to do, make a backup and make sure you know what you are doing! Issues The HPE Dynamic Smart Array B140i is a software RAID device. While it s convenient for some users that software RAID gets supported in the UEFI boot process, generally software RAID is a bad idea. Also my system has hot-swap drive caddies but the controller doesn t support hot-swap. So the first thing to do was to configure the array controller to run in AHCI mode and give up on using hot-swap drive caddies for hot-swap. I tested all the documented ways of scanning for new devices and nothing other than a reboot made the kernel recognise a new SATA disk. According to specs provided by Dell and HP the ML110 Gen9 makes less noise than the PowerEdge T320, according to my own observations the reverse is the case. I don t know if this is because of Dell being more conservative in their specs than HP or because of how dBA is measured vs my own personal annoyance thresholds for sounds. As the system makes more noise than I m comfortable with I plan to build a rubber enclosure for the rear of the system to reduce noise, that will be the subject of another post. For Australian readers Bunnings has some good deals on rubber floor mats that can be used to reduce server noise. The server doesn t have sound hardware, while one could argue that servers don t need sound there are some server uses for sound hardware such as using line input as a source of entropy. Also for a manufacturer it might be a benefit to use the same motherboard for workstations and servers. Fortunately a friend gave me a nice set of Logitech USB speakers a few years ago that I hadn t previously had a cause to use, so that will solve the problem for me (I don t need line-in on a workstation). UEFI and Memtest I decided to try UEFI boot for something new (in the past I d only used UEFI boot for a server that only had large disks). In the past I ve booted all my own systems with BIOS boot because I m familiar with it and they all have SSDs for booting which are less than 2TB in size (until recently 2TB SSDs weren t affordable for my personal use). The Debian UEFI wiki page is worth reading [3]. The Debian Wiki page about ProLiant servers [4] is worth reading too. Memtest86+ doesn t support EFI booting (just goes to a black screen) even though Debian/Buster puts in a GRUB entry for it (Debian bug #695246 was filed for this in 2012). Also on my ML110 Memtest86+ doesn t report the RAM speed (a known issue on Memtest86+). Comments on the net say that Memtest86+ hasn t been maintained for a long time and Memtest86 (the non-free version) has been updated more recently. So far I haven t seen a system with ECC RAM have a memory problem that could be detected by Memtest86+, the memory problems I ve seen on ECC systems have been things that prevent booting (RAM not being recognised correctly), that are detected by the BIOS as ECC errors before booting, or that are reported by the kernel as ECC errors at run time (happened years ago and I can t remember the details). Overall I m not a fan of EFI with the way it currently works in Debian. It seems to add some of the GRUB functionality into the BIOS and then use that to load GRUB. It seems that EFI can do everything you need and it would be better to just have a single boot loader not two of them chained. Power Supply There are a range of PSUs for the ML110, the one I have has the smallest available PSU (350W) and doesn t have a PCIe power cable (the one used for video cards). Here is the HP document which shows the cabling for the various ML110 Gen8 PSUs [5], I have the 350W PSU. One thing I ve considered is whether I could make an adaptor from the drive bay power to the PCIe connector. A quick web search indicates that 4 SAS disks when active can take up to 75W more power than a system with no disks. If that s the case then the 2 spare drive bay connectors which can each handle 4 disks should be able to supply 150W. As a 6 pin PCIe power cable (GPU power cable) is rated at 75W that should be fine in theory (here s a page with the pinouts for PCIe power connectors [6]). My video card is a Radeon R7 260X which apparently takes about 113W all up so should be taking less than 75W from the PCIe power cable. All I really want is YouTube, Netflix, and text editing at 4K resolution. So I don t need much in terms of 3D power. KDE uses some of the advanced features of modern video cards, but it doesn t compare to 3D gaming. According to the Wikipedia page for Radeon RX 500 series [7] the RX560 supports DisplayPort 1.4 and HDMI 2.0 (both of which do 4K@60Hz) and has a TDP of 75W. So a RX560 video card seems like a good option that will work in any system that doesn t have a spare PCIe power cable. I ve just ordered one of those for $246 so hopefully that will arrive in a week or so. PCI Fan The ML110 Gen9 has an optional PCIe fan and baffle to cool PCIe cards (part number 784580-B21). Extra cooling of PCIe cards is a good thing, but $400 list price (and about $50 ebay price) for the fan and baffle is unpleasant. When I boot the system with a PCIe dual-ethernet card and two PCIe NVMe cards it gives a BIOS warning on boot, when I add a video card it refuses to boot without the extra fan. It s nice that the system makes sure it doesn t get into a thermal overload situation, but it would be nicer if they just shipped all necessary fans with it instead of trying to get more money out of customers. I just bought a PCI fan and baffle kit for $60. Conclusion In spite of the unexpected expense of a new video card and PCI fan the overall cost of this system is still low, particularly when considering that I ll find another use for the video card which needs and extra power connector. It is disappointing that HP didn t supply a more capable PSU and fit all the fans to all models, the expectation of a server is that you can just do server stuff not have to buy extra bits before you can do server stuff. If you want to install Tesla GPUs or something then it s expected that you might need to do something unusual with a server, but the basic stuff should just work. A single processor tower server should be designed to function as a deskside workstation and be able to handle an average video card. Generally it s a nice computer, I look forward to getting the next deliveries of parts so I can make it work properly.

10 May 2021

Russell Coker: Minikube and Debian

I just started looking at the Kubernetes documentation and interactive tutorial [1], which incidentally is really good. Everyone who is developing a complex system should look at this to get some ideas for online training. Here are some notes on setting it up on Debian. Add Kubernetes Apt Repository
deb https://apt.kubernetes.io/ kubernetes-xenial main
First add the above to your apt sources configuration (/etc/apt/sources.list or some file under /etc/apt/sources.list.d) for the kubectl package. Ubuntu Xenial is near enough to Debian/Buster and Debian/Unstable that it should work well for both of them. Then install the GPG key 6A030B21BA07F4FB for use by apt:
gpg --recv-key 6A030B21BA07F4FB
gpg --list-sigs 6A030B21BA07F4FB
gpg --export 6A030B21BA07F4FB   apt-key add -
The Google key in question is not signed. Install Packages for the Tutorial The online training is based on minikube which uses libvirt to setup a KVM virtual machine to do stuff. To get this running you need to have a system that is capable of running KVM (IE the BIOS is set to allow hardware virtualisation). It MIGHT work on QEMU software emulation without KVM support (technically it s possible but it would be slow and require some code to handle that), I didn t test if it does. Run the following command to install libvirt, kvm, and dnsmasq (which minikube requires) and kubectl on Debian/Buster:
apt install libvirt-clients libvirt-daemon-system qemu-kvm dnsmasq kubectl
For Debian/Unstable run the following command:
apt install libvirt-clients libvirt-daemon-system qemu-system-x86 dnsmasq kubectl
To run libvirt as non-root without needing a password for everything you need to add the user in question to the libvirt group. I recommend running things as non-root whenever possible. In this case entering a password for everything will probably be more pain than you want. The Debian Wiki page about KVM [2] is worth reading. Install Minikube Test Environment Here is the documentation for installing Minikube [3]. Basically just download a single executable from the net, put it in your $PATH, and run it. Best to use non-root for that. Also you need at least 3G of temporary storage space in the home directory of the user that runs it. After installing minikube run minikube start which will download container image data and start it up. Then you can run commands like the following to see what it has done.
# get overview of virsh commands
virsh help
# list domains
virsh --connect qemu:///system list
# list block devices a domain uses
virsh --connect qemu:///system domblklist minikube
# show stats on block device usage
virsh --connect qemu:///system domblkstat minikube hda
# list virtual networks
virsh --connect qemu:///system net-list
# list dhcp leases on a virtual network
virsh --connect qemu:///system net-dhcp-leases minikube-net
# list network filters
virsh --connect qemu:///system nwfilter-list
# list real network interfaces
virsh --connect qemu:///system iface-list

Russell Coker: Echo Chambers vs Epistemic Bubbles

C Thi Nguyen wrote an interesting article about the difficulty of escaping from Echo Chambers and also mentions Epistemic Bubbles [1]. An Echo Chamber is a group of people who reinforce the same ideas and who often preemptively strike against opposing ideas (for example the right wing denigrating mainstream media to prevent their followers from straying from their approved message). An Epistemic Bubble is a group of people who just happen to not have contact with certain different ideas. When reading that article I wondered about what bubbles I and the people I associate with may be in. One obvious issue is that I have little communication with people who don t write in English and also little communication with people who are poor. So people who are poor and who can t write in English (which means significant portions of the population of India and Africa) are out of communication range for me. There are many situations that are claimed to be bubbles such as white people who are claimed to be innocent of racial issues because they only associate with other white people and men in the IT industry who are claimed to be innocent of sexism because they don t associate with women in the IT industry. But I think they are more of an echo chamber issue, if a white American doesn t access any of the variety of English language media produced by Afro Americans and realise that there s a racial problem it s because they don t want to see it and deliberately avoid looking at evidence. If a man in the IT industry doesn t access any of the media produced by women in tech and realise there are problems with sexism then it s because they don t want to see it. When is it OK to Reject a Group? The Ad Hominem Wikipedia page has a good analysis of different types of Ad Hominem arguments [2]. But the criteria for refuting a point in a debate are very different to the criteria used to determine which sources you should trust when learning about a topic. For example it s theoretically possible for someone to be good at computer science while also thinking the world is flat. In a debate about some aspect of computer programming it would be a fallacious Ad Hominem argument to say you think the Earth is flat therefore you can t program a computer . But if you do a Google search for information on computer programming and one of the results is from earthisflat.com then it would probably save time to skip reading that one. If only one person supports an idea then it s quite likely to be wrong. Good ideas tend to be supported by multiple people and for any good idea you will find a supporter who doesn t appear to have any ideas that are obviously wrong. One of the problems we have as a society now is determining the quality of data (ideas, claims about facts, opinions, communication/spam, etc). When humans have to do that it takes time and energy. Shortcuts can make things easier. Some shortcuts I use are that mainstream media articles are usually more reliable than social media posts (even posts by my friends) and that certain media outlets are untrustworthy (like Breitbart). The next step is that anyone who cites a bad site like Breitbart as factual (rather than just an indication of what some extremists believe) is unreliable. For most questions that you might search for on the Internet there is a virtually endless supply of answers, the challenge is not finding an answer but finding a correct answer. So eliminating answers that are unlikely to be correct is an important part of the search. If someone is citing references to support their argument and they can only cite fringe or extremist sites then I won t be convinced. Now someone could turn that argument around and claim that a site I reference such as the New York Times is wrong. If I find that my ideas were based on a claim that can only be found on the NYT then I will reconsider the issue. While I think that the NYT is generally accurate they are capable of making mistakes and if they are the sole source for claims that go against other claims then I will be hesitant to accept such claims. Newspapers often have exclusive articles based on their own research, but such articles always inspire investigation from other newspapers so other articles appear either supporting or questioning the claims in the exclusive. Saving Time When Interacting With Members of Echo Chambers Convincing a member of a cult or echo chamber of anything is not likely. When in discussions with them the focus should be on the audience and on avoiding wasting much time while also not giving them the impression that you agree with them. A common thing that members of echo chambers say is I don t have time to read about that when you ask if they have read a research paper or a news article. I don t have time to listen to people who can t or won t learn before speaking, there just isn t any value in that. Also if someone has a list of memes that takes more than 15 minutes to recite then they have obviously got time for reading things, just not reading outside their echo chamber. Conversations with members of echo chambers seem to be state free. They make a claim and you reject it, but regardless of the logical flaws you point out or the counter evidence you cite they make the same claim again the next time you speak to them. This seems to be evidence supporting the claim that evangelism is not about converting other people but alienating cult members from the wider society [3] (the original Quora text seems unavailable so I ve linked to a Reddit copy). Pointing out that they had made a claim previously and didn t address the issues you had with it seems effective, such discussions seem to be more about performance so you want to perform your part quickly and efficiently. Be aware of false claims about etiquette. It s generally regarded as polite not to disagree much with someone who invites you to your home or who has done some favour for you, but that is no reason for tolerating an unwanted lecture about their echo chamber. Anyone who tries to create a situation where it seems rude of you not to listen to them saying things that they know will offend you is being rude, much ruder than telling them you are sick of it. Look for specific claims that can be disproven easily. The claim that the Roman Salute is different from the Hitler Salute is one example that is easy to disprove. Then they have to deal with the issue of their echo chamber being wrong about something.

Russell Coker: More EVM

This is another post about EVM/IMA which has it s main purpose providing useful web search results for problems. However if reading it on a planet feed inspires someone to play with EVM/IMA then that s good too, it s interesting technology. When using EVM/IMA in the Linux kernel if dmesg has errors like op=appraise_data cause=missing-HMAC the missing-HMAC means that the error code in the kernel source is INTEGRITY_NOLABEL which has a comment No security.evm xattr . You can check for the xattr on a file with the following command (this example has the security.evm xattr):
# getfattr -d -m - /etc/fstab 
getfattr: Removing leading '/' from absolute path names
# file: etc/fstab
security.evm=0sAwICqGOsfwCAvgE9y9OP74QxJ/I+3eOSF2n2dM51St98z/7LYHFd9rfGTvssvhTSYL9G8cTdRAH8ozggJu7VCzggW1REoTjnLcPeuMJsrMbW3DwVrB6ldDmJzyenLMjnIHmRDDeK309aRbLVn2ueJZ07aMDcSr+sxhOOAQ/GIW4SW8L1AKpKn4g=
security.ima=0sAT+Eivfxl+7FYI+Hr9K4sE6IieZ+
security.selinux="system_u:object_r:etc_t:s0"
If dmesg has errors like op=appraise_data cause=invalid-HMAC the invalid-HMAC means that the error code in the kernel source is INTEGRITY_FAIL which has a comment Invalid HMAC/signature . These errors are from the evm_verifyxattr() function in Linux kernel 5.11.14. The error evm: HMAC key is not set means that the evm key is not initialised, this means the key needs to be loaded into the kernel and EVM is initialised by the command echo 1 > /sys/kernel/security/evm (or possibly some equivalent from a utility like evmctl). When the key is loaded the kernel gives the message evm: key initialized and after that /sys/kernel/security/evm is read-only. If there is something wrong with the key the kernel gives the message evm: key initialization failed , it seems that the way to determine if your key is good is to try writing 1 to /sys/kernel/security/evm and see what happens. After that the command cat /sys/kernel/security/evm should return 3 . The Gentoo wiki has good documentation on how to create and load the keys which has to be done before initialising EVM [1]. I ll write more about that in another post.

3 May 2021

Russell Coker: DNS, Lots of IPs, and Postal

I decided to start work on repeating the tests for my 2006 OSDC paper on Benchmarking Mail Relays [1] and discover how the last 15 years of hardware developments have changed things. There have been software changes in that time too, but nothing that compares with going from single core 32bit systems with less than 1G of RAM and 60G IDE disks to multi-core 64bit systems with 128G of RAM and SSDs. As an aside the hardware I used in 2006 wasn t cutting edge and the hardware I m using now isn t either. In both cases it s systems I bought second hand for under $1000. Pedants can think of this as comparing 2004 and 2018 hardware. BIND I decided to make some changes to reflect the increased hardware capacity and use 2560 domains and IP addresses, which gave the following errors as well as a startup time of a minute on a system with two E5-2620 CPUs.
May  2 16:38:37 server named[7372]: listening on IPv4 interface lo, 127.0.0.1#53
May  2 16:38:37 server named[7372]: listening on IPv4 interface eno4, 10.0.2.45#53
May  2 16:38:37 server named[7372]: listening on IPv4 interface eno4, 10.0.40.1#53
May  2 16:38:37 server named[7372]: listening on IPv4 interface eno4, 10.0.40.2#53
May  2 16:38:37 server named[7372]: listening on IPv4 interface eno4, 10.0.40.3#53
[...]
May  2 16:39:33 server named[7372]: listening on IPv4 interface eno4, 10.0.47.0#53
May  2 16:39:33 server named[7372]: listening on IPv4 interface eno4, 10.0.48.0#53
May  2 16:39:33 server named[7372]: listening on IPv4 interface eno4, 10.0.49.0#53
May  2 16:39:33 server named[7372]: listening on IPv6 interface lo, ::1#53
[...]
May  2 16:39:36 server named[7372]: zone localhost/IN: loaded serial 2
May  2 16:39:36 server named[7372]: all zones loaded
May  2 16:39:36 server named[7372]: running
May  2 16:39:36 server named[7372]: socket: file descriptor exceeds limit (123273/21000)
May  2 16:39:36 server named[7372]: managed-keys-zone: Unable to fetch DNSKEY set '.': not enough free resources
May  2 16:39:36 server named[7372]: socket: file descriptor exceeds limit (123273/21000)
The first thing I noticed is that a default configuration of BIND with 2560 local IPs (when just running in the default recursive mode) takes a minute to start and needed to open over 100,000 file handles. BIND also had some errors in that configuration which led to it not accepting shutdown requests. I filed Debian bug report #987927 [2] about this. One way of dealing with the errors in this situation on Debian is to edit /etc/default/named and put in the following line to allow BIND to access to many file handles:
OPTIONS="-u bind -S 150000"
But the best thing to do for BIND when there are many IP addresses that aren t going to be used for DNS service is to put a directive like the following in the BIND configuration to specify the IP address or addresses that are used for the DNS service:
listen-on   10.0.2.45;  ;
I have just added the listen-on and listen-on-v6 directives to one of my servers with about a dozen IP addresses. While 2560 IP addresses is an unusual corner case it s not uncommon to have dozens of addresses on one system. dig When doing tests of Postfix for relaying mail I noticed that mail was being deferred with DNS problems (error was Host or domain name not found. Name service error for name=a838.example.com type=MX: Host not found, try again . I tested the DNS lookups with dig which failed with errors like the following:
dig -t mx a704.example.com
socket.c:1740: internal_send: 10.0.2.45#53: Invalid argument
socket.c:1740: internal_send: 10.0.2.45#53: Invalid argument
socket.c:1740: internal_send: 10.0.2.45#53: Invalid argument
; <
> DiG 9.16.13-Debian <
> -t mx a704.example.com
;; global options: +cmd
;; connection timed out; no servers could be reached
Here is a sample of the strace output from tracing dig:
bind(20,  sa_family=AF_INET, sin_port=htons(0), 
sin_addr=inet_addr("0.0.0.0") , 16) = 0
recvmsg(20,  msg_namelen=128 , 0)       = -1 EAGAIN (Resource temporarily 
unavailable)
write(4, "\24\0\0\0\375\377\377\377", 8) = 8
sendmsg(20,  msg_name= sa_family=AF_INET, sin_port=htons(53), 
sin_addr=inet_addr("10.0.2.45") , msg_
namelen=16, msg_iov=[ iov_base="86\1 
\0\1\0\0\0\0\0\1\4a704\7example\3com\0\0\17\0\1\0\0)\20\0\0\0\0
\0\0\f\0\n\0\10's\367\265\16bx\354", iov_len=57 ], msg_iovlen=1, 
msg_controllen=0, msg_flags=0 , 0) 
= -1 EINVAL (Invalid argument)
write(2, "socket.c:1740: ", 15)         = 15
write(2, "internal_send: 10.0.2.45#53: Invalid argument", 45) = 45
write(2, "\n", 1)                       = 1
futex(0x7f5a80696084, FUTEX_WAIT_PRIVATE, 0, NULL) = 0
futex(0x7f5a80696010, FUTEX_WAKE_PRIVATE, 1) = 0
futex(0x7f5a8069809c, FUTEX_WAKE_PRIVATE, 1) = 1
futex(0x7f5a80698020, FUTEX_WAKE_PRIVATE, 1) = 1
sendmsg(20,  msg_name= sa_family=AF_INET, sin_port=htons(53), 
sin_addr=inet_addr("10.0.2.45") , msg_namelen=16, msg_iov=[ iov_base="86\1 
\0\1\0\0\0\0\0\1\4a704\7example\3com\0\0\17\0\1\0\0)\20\0\0\0\0\0\0\f\0\n\0\10's\367\265\16bx\354", 
iov_len=57 ], msg_iovlen=1, msg_controllen=0, msg_flags=0 , 0) = -1 EINVAL 
(Invalid argument)
write(2, "socket.c:1740: ", 15)         = 15
write(2, "internal_send: 10.0.2.45#53: Invalid argument", 45) = 45
write(2, "\n", 1)
Ubuntu bug #1702726 claims that an insufficient ARP cache was the cause of dig problems [3]. At the time I encountered the dig problems I was seeing lots of kernel error messages neighbour: arp_cache: neighbor table overflow which I solved by putting the following in /etc/sysctl.d/mine.conf:
net.ipv4.neigh.default.gc_thresh3 = 4096
net.ipv4.neigh.default.gc_thresh2 = 2048
net.ipv4.neigh.default.gc_thresh1 = 1024
Making that change (and having rebooted because I didn t need to run the server overnight) didn t entirely solve the problems. I have seen some DNS errors from Postfix since then but they are less common than before. When they happened I didn t have that error from dig. At this stage I m not certain that the ARP change fixed the dig problem although it seems likely (it s always difficult to be certain that you have solved a race condition instead of made it less common or just accidentally changed something else to conceal it). But it is clearly a good thing to have a large enough ARP cache so the above change is probably the right thing for most people (with the possibility of changing the numbers according to the required scale). Also people having that dig error should probably check their kernel message log, if the ARP cache isn t the cause then some other kernel networking issue might be related. Preliminary Results With Postfix I m seeing around 24,000 messages relayed per minute with more than 60% CPU time idle. I m not sure exactly how to count idle time when there are 12 CPU cores and 24 hyper-threads as having only 1 process scheduled for each pair of hyperthreads on a core is very different to having half the CPU cores unused. I ran my script to disable hyper-threads by telling the Linux kernel to disable each processor core that has the same core ID as another, it was buggy and disabled the second CPU altogether (better than finding this out on a production server). Going from 24 hyper-threads of 2 CPUs to 6 non-HT cores of a single CPU didn t change the thoughput and the idle time went to about 30%, so I have possibly halved the CPU capacity for these tasks by disabling all hyper-threads and one entire CPU which is surprising given that I theoretically reduced the CPU power by 75%. I think my focus now has to be on hyper-threading optimisation. Since 2006 the performance has gone from ~20 messages per minute on relatively commodity hardware to 24,000 messages per minute on server equipment that is uncommon for home use but which is also within range of home desktop PCs. I think that a typical desktop PC with a similar speed CPU, 32G of RAM and SSD storage would give the same performance. Moore s Law (that transistor count doubles approximately every 2 years) is often misquoted as having performance double every 2 years. In this case more than 1024* the performance over 15 years means the performance doubling every 18 months. Probably most of that is due to SATA SSDs massively outperforming IDE hard drives but it s still impressive. Notes I ve been using example.com for test purposes for a long time, but RFC2606 specifies .test, .example, and .invalid as reserved top level domains for such things. On the next iteration I ll change my scripts to use .test. My current test setup has a KVM virtual machine running my bhm program to receive mail which is taking between 20% and 50% of a CPU core in my tests so far. While that is happening the kvm process is reported as taking between 60% and 200% of a CPU core, so kvm takes as much as 4* the CPU of the guest due to the virtual networking overhead even though I m using the virtio-net-pci driver (the most efficient form of KVM networking for emulating a regular ethernet card). I ve also seen this in production with a virtual machine running a ToR relay node. I ve fixed a bug where Postal would try to send the SMTP quit command after encountering a TCP error which would cause an infinite loop and SEGV.

28 April 2021

Russell Coker: Links April 2021

Dr Justin Lehmiller s blog post comparing his official (academic style) and real biographies is interesting [1]. Also the rest of his blog is interesting too, he works at the Kinsey Institute so you know he s good. Media Matters has an interesting article on the spread of vaccine misinformation on Instagram [2]. John Goerzen wrote a long post summarising some of the many ways of having a decentralised Internet [3]. One problem he didn t address is how to choose between them, I could spend months of work to setup a fraction of those services. Erasmo Acosta wrote an interesting medium article Could Something as Pedestrian as the Mitochondria Unlock the Mystery of the Great Silence? [4]. I don t know enough about biology to determine how plausible this is. But it is a worry, I hope that humans will meet extra-terrestrial intelligences at some future time. Meredith Haggerty wrote an insightful Medium article about the love vs money aspects of romantic comedies [5]. Changes in viewer demographics would be one factor that makes lead actors in romantic movies significantly less wealthy in recent times. Informative article about ZIP compression and the history of compression in general [6]. Vice has an insightful article about one way of taking over SMS access of phones without affecting voice call or data access [7]. With this method the victom won t notice that they are having their sservice interfered with until it s way too late. They also explain the chain of problems in the US telecommunications industry that led to this. I wonder what s happening in this regard in other parts of the world. The clown code of ethics (8 Commandments) is interesting [8]. Sam Hartman wrote an insightful blog post about the problems with RMS and how to deal with him [9]. Also Sam Whitton has an interesting take on this [10]. Another insightful post is by Selam G about RMS long history of bad behavior and the way universities are run [11]. Cory Doctorow wrote an insightful article for Locus about free markets with a focus on DRM on audio books [12]. We need legislative changes to fix this!

25 April 2021

Russell Coker: Scanning with a MFC-9120CN on Bullseye

I previously wrote about getting a Brother MFC-9120CN multifunction printer/scanner to print on Linux [1]. I had also got it scanning which I didn t blog about.
found USB scanner (vendor=0x04f9, product=0x021d) at libusb:003:002
I recently upgraded that Linux system to Debian/Testing (which will soon be released as Debian/Bullseye) and scanning broke. The command sane-find-scanner would find the USB connected scanner (with the above output), but scanimage -L didn t. It turned out that I had to edit /etc/sane.d/dll.d/hplip which had a single uncommented line of hpaio and replace that with brother3 to make SANE load the driver /usr/lib64/sane/libsane-brother3.so from the brscan3 package (which Brother provided from their web site years ago). I have the following script to do the scanning (which can run as non-root):
#!/bin/bash
set -e
if [ "$1" == "" ]; then
  echo "specify output filename"
  exit 1
fi
TMP=$(mktemp)
scanimage > $TMP
convert $TMP $1
rm $TMP
Final Note This blog post doesn t describe everything that needs to be done to setup a scanner, I already had part of it setup from 10 years ago. But for anyone who finds this after having trouble, /etc/sane.d/dll.d is one place you should look for important configuration (especially if sane-find-scanner works and scanimage -L fails). Also the Brother drivers are handy to have although I apparently had it working in the past with the hpaio driver from HP (the Brother device emulates a HP device).

22 April 2021

Russell Coker: HP ML350P Gen8

I m playing with a HP Proliant ML350P Gen8 server (part num 646676-011). For HP servers ML means tower (see the ProLiant Wikipedia page for more details [1]). For HP servers the generation indicates how old the server is, Gen8 was announced in 2012 and Gen10 seems to be the current generation. Debian Packages from HP
wget -O /usr/local/hpePublicKey2048_key1.pub https://downloads.linux.hpe.com/SDR/hpePublicKey2048_key1.pub
echo "# HP RAID" >> /etc/apt/sources.list
echo "deb [signed-by=/usr/local/hpePublicKey2048_key1.pub] http://downloads.linux.hpe.com/SDR/downloads/MCP/Debian/ buster/current non-free" >> /etc/apt/sources.list
The above commands will setup the APT repository for Debian/Buster. See the HP Downloads FAQ [2] for more information about their repositories. hponcfg This package contains the hponcfg program that configures ILO (the HP remote management system) from Linux. One noteworthy command is hponcfg -r to reset the ILO, something you should do before selling an old system. ssacli This package contains the ssacli program to configure storage arrays, here are some examples of how to use it:
# list controllers and show slot numbers
ssacli controller all show
# list arrays on controller identified by slot and give array IDs
ssacli controller slot=0 array all show
# show details of one array
ssacli controller slot=0 array A show
# show all disks on one controller
ssacli controller slot=0 physicaldrive all show
# show config of a controller, this gives RAID level etc
ssacli controller slot=0 show config
# delete array B (you can immediately pull the disks from it)
ssacli controller slot=0 array B delete
# create an array type RAID0 with specified drives, do this with one drive per array for BTRFS/ZFS
ssacli controller slot=0 create type=arrayr0 drives=1I:1:1
When a disk is used in JBOD mode just under 33MB will be used at the end of the disk for the RAID metadata. If you have existing disks with a DOS partition table you can put it in a HP array as a JBOD and it will work with all data intact (GPT partition table is more complicated). When all disks are removed from the server the cooling fans run at high speed, this would be annoying if you wanted to have a diskless workstation or server using only external storage. ssaducli This package contains the ssaducli diagnostic utility for storage arrays. The SSD wear gauge report doesn t work for the 2 SSDs I tested it on, maybe it only supports SAS SSDs not SATA SSDs. It doesn t seem to do anything that I need. storcli This package contains both 32bit and 64bit versions of the MegaRAID utility and deletes whichever one doesn t match the installation in the package postinst, so it fails debsums checks etc. The MegaRAID utility is for a different type of RAID controller to the Smart Storage Array (AKA SSA) that the other utilities work with. As an aside it seems that there are multiple types of MegaRAID controller, the management program from the storcli package doesn t work on a Dell server with MegaRAID. They should have made separate 32bit and 64bit versions of this package. Recommendations Here is HP page for downloading firmware updates (including security updates) [3], you have to login first and have a warranty. This is legal but poor service. Dell servers have comparable prices (on the second hand marker) and comparable features but give free firmware updates to everyone. Dell have overall lower quality of Debian packages for supporting utilities, but a wider range of support so generally Dell support seems better in every way. Dell and HP hardware seems of equal quality so overall I think it s best to buy Dell. Suggestions for HP Finding which of the signing keys to use is unreasonably difficult. You should get some HP employees to sign the HP keys used for repositories with their personal keys and then go to LUG meetings and get their personal keys well connected to the web of trust. Then upload the HP keys to the public key repositories. You should also use the same keys for signing all versions of the repositories. Having different keys for the different versions of Debian wastes people s time. Please provide firmware for all users, even if they buy systems second hand. It is in your best interests to have systems used long-term and have them run securely. It is not in your best interests to have older HP servers perform badly. Having all the fans run at maximum speed when power is turned on is a standard server feature. Some servers can throttle the fan when the BIOS is running, it would be nice if HP servers did that. Having ridiculously loud fans until just before GRUB starts is annoying.

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