Yesterday evening my system became slower and slower, restarting it to the newest generation took more than an hour (I went to bed before it finished), this morning I wanted to quickly check something in my config and triggered a nix build of the dev shell through direnv. The build of the environment never finished and the system instantly got slow again. Looking at
htop I found a
nix deamon process beeing in “uninteruptable sleep” as well as my systems load beein on 15+ on the short term average, mid and long term of course have been lower but were on the rising tide. When load was at 20 and system mostly irrespondable I issued a reboot from a TTY. Reaching end of the shutdown took more than 10 minutes of which there was a lot time spent on waiting for disks to be unmounted and the nix related services shutting down.
I booted into earlier available generations and each one was quicker to boot than the one before, but all but the last had the problem that either SDDM or a nix deamon became “uninterubtable sleep”, even after multiple tries.
What is the easiest way to inspect the differences between those generations? The only one I am aware off, is the kernel version (5.4.x for all of them, but differences in the “x”). I do not remember exact versions.
I left the computer in the seemingly working generation to observe how it behaves after some hours of uptime, and want to retry the more recent generations again this evening.
Though let me ask in advance, do you have any tips on how to properly debug such issues?
If it is of any help, the system is configured through flakes, though the span of generations I have tried might still be from the non-flake times…