woes of snapper

another linux debugging post! yayy! i love things breaking 💛💛

so what happened this time is my system was freezing up. well not really—just the io was incredibly slow, so as a result stuff was blocked. btop for some reason showed this as 100% cpu usage, which was incredibly misleading. honestly, btop is pretty terrible if you actually want to know whats going on, its mostly just a pretty tool, but i disgress.

once i dug out top and figured out that cpu was actually like 85% idle, i suspected some btrfs bull now. btrfs is always running some shit in the background. from sudo btrfs qgroup show /, i saw that it was deleting 38 snapshots and that i had 450 total snapshots.

well now i'd done it. i was installing and uninstalling a bunch of stuff to try to get metadata on my audio files (i ended up using picard ) and since i was using snapper, it created a snapshot every time. i'm not sure why the limit was set to 450, that's quite absurd to be frank. might be something with cachyos defaults.

it was deleting all 38 snapshots and causing everything to lock up, since i'm running a hdd and, well, let's just say it's not exactly the fastset. i decreased the max snapshots to 40 which should, in theory make deleting snapshots much faster—btrfs is deduplicated so more snapshots means it has to calculate more to figure out what to actually delete. for future reference, i should probably run with SKIP_AUTOSNAP=1 when doing lots of pacman operations.

i also found while going through dmesg an intel driver bug. arch wiki says i can fix this with i915.enable_psr=0. hopefully it works.