dysnomia VS Intel-Linux-Processor-Microcode-Data-Files

NixOS doesn't have much, if anything, in the way of state management for services like databases. The Nix-iest way I know of managing those things is to write Dysnomia plugins for those things. But you'll have to figure out managing their internal state yourself to do that, e.g., with something like Liquibase or Flyway or something like that.

Depends on how the state is stored. If it's in configuration, Nix generated it and it lives immutable in the Nix store, so Nix will just point out it to the old version on rollback.

If it's something like the content of a SQL database, which lives outside the Nix store and which Nix did not generate, you need some other tool (like a filesystem snapshot, maybe) to perform the rollback. I think CoW filesystems sometimes have performance issues with DBs, though, so I'm not sure that's always the approach you'd take.

The Nix ecosystem does have a fairly mature tool for managing stateful components that live outside the Nix store, though: https://github.com/svanderburg/dysnomia

It's been around for a long time. Idk who all is using it

https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/blob/main/releasenote.md looks like they released a new microcode (24000024) affecting these units on Feb 14th this year.

Package: intel-microcode Version: 3.20221108.1 Priority: optional Section: non-free/admin Maintainer: Henrique de Moraes Holschuh Installed-Size: 6460 kB Depends: iucode-tool (>= 1.0) Recommends: initramfs-tools (>= 0.113~) Conflicts: microcode.ctl (<< 0.18~0) Homepage: https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files Tag: hardware::TODO, role::app-data, use::driver Download-Size: 4509 kB APT-Sources: http://deb.debian.org/debian testing/non-free amd64 Packages Description: Processor microcode firmware for Intel CPUs

They have been sort of cracked, but it doesn't matter. The web or chain of trust of those updates from the vendor to the processor is what matters. They're at least CRC checked to prevent loading corrupt files.

https://ieeeaccess.ieee.org/featured-articles/reverseenginee...

https://github.com/intel/Intel-Linux-Processor-Microcode-Dat...

https://github.com/platomav/CPUMicrocodes

Not to “well aktchually”, but all modern processors do have regularly updated microcode that’s uploaded at boot time - https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files

6-94-3 would become 6-5E-3. https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/blob/6c0c4691e5bb446e0e428ebca595164709c59586/intel-ucode/06-5e-03

OpenBSD kernel has no support for loading microcode on AMD CPUs, A number of issues/errata on AMD systems may be fixed as part of AGESA updates, in addition to microcode as part of BIOS/firmware updates. While there have been microcode updates released for Zen+ or newer CPUs, but these seem to be less frequent than Intel.

Is it anymore of a "magic incantation" than the linux-image-XYZ package which controls which OS kernel is installed?

If you want to see when Intel issues new microcode updates, it is all available on their GitHub: https://github.com/intel/Intel-Linux-Processor-Microcode-Dat...