I just finished updating my server from 7.2.4 to 7.3.2 and ran into a weird "issue".

My cache pool is showing up as degraded, and I received a notification stating that I have a missing drive in my cache pool (Crucial_CT500MX200SSD1_14520E6A2323). I had some drive errors showing up after the update for that drive (2-3 reads, 1 write) but scrubbed it and reset the stats and all is good on that front.

The issue is that drive does indeed show up in my cache pool, and the other drive is a replacement drive installed last year. It appears like it never replaced the actual missing drive with the new one. My VMs and docker containers are all working fine.

knight-diagnostics-20260922-1302.zip

Keep in mind that the pool was already degraded; we were just not getting any notifications since pool monitoring is new in 7.3.

To fix this, and with the the array runing type

btrfs balance start -f dconvert=single,soft mconvert=single,soft /mnt/cache

when that's done

btrfs device remove missing /mnt/cache

Then stop the array and reimport the pool with the good device only:

on main click on the first device for that pool and then "remove pool"

back on main, create a new pool with the same name and 1 slot

assign the pool device (sdb), leave the filesystem set to auto

start the array to import the pool

If the pool mounts, stop thte array and add the other device again.

1 hour ago, JorgeB said:

Keep in mind that the pool was already degraded; we were just not getting any notifications since pool monitoring is new in 7.3.

Figured that it was something I missed back in the day and never noticed it.

For any future visitors (or more likely myself when I mess this up again), the correct command is :

btrfs balance start -f -dconvert=single,soft -mconvert=single,soft /mnt/cache

11 hours ago, Psycho said:

the correct command is :

Yep, sorry about that