Read-only file system on Cache drive

[Utakka]

Hey guys,

Apparently I have a problem with my cache drives, but I have no idea what causes it..

/var/log/docker.log.1 is full of 'read-only file system' errors.
Because of that I checked the cache drives. One of them has the following lines in Disk Log Info:

Jun 24 03:41:08 NAS kernel: BTRFS error (device sdb1): unable to find ref byte nr 47101054976 parent 0 root 5 owner 1045137 offset 0
Jun 24 03:41:08 NAS kernel: BTRFS: error (device sdb1) in __btrfs_free_extent:6802: errno=-2 No such entry
Jun 24 03:41:08 NAS kernel: BTRFS info (device sdb1): forced readonly

What can I do to solve this problem?

nas-diagnostics-20200624-1332.zip

[JorgeB]

Best bet it to backup cache, re-format the pool and restore the data.

[Utakka]

Thank you!
 

Cache data is no problem, but I have one VM and one Docker Container running on the cache pool. Is there any chance for an (relatively) easy way to backup and restore these two? Can they be moved to the main array?

[JorgeB]

Because it's read-only it can't be easily moved with the mover, but you should still be able to use your favorite utility to copy it, e.g., see here for a way to do it.