Unraid BTRFS Issues

One of my BTRFS pools, which was RAID 1 corrupted and wouldn’t mount.

I want to say docker updates overloaded the size of the docker file.

I probably did this all wrong, but I got a lot of the data from it, so I provided some commands that might help others in the future.

Make sure to put Unraid into maintenance mode.

Below are just examples since I didn’t record exactly what I did.

To mount the degraded RAID configuration. Choose the primary partition/drive to mount somewhere.

#mount degraded RAID
mount -o degraded /dev/mapper/[partition] /mnt

# to unmount
umount /mnt

To check the filesystem and hopefully fix the filesystem issue.

#shows you the filesystem
btrfs fi show /dev/sdd

#starts the scrub process
btrfs scrub start /mnt

#checks the scrub process status
btrfs scrub status /mnt

You can also use this to monitor the status instead of running the last line above over and over again.

#this will check the status of the scrub every second

watch -n 1 btrfs scrub status /mnt

I was told not to use this since it might screw up the filesystem, but my filesystem was already screwed up 🙂 This checks and tries to repair the filesystem.

btrfs check --repair /dev/sdd