Just noticed these errors in the log. sdf is one SSD out of 2 in my cache pool.
From other threads I think I need to run BTRFS scrub.
I have stopped all VMs and docker.
Before I did that I tried to take a backup of the cache drive to an unassigned disk, however some files failed with "cannot access source file"
I have daily snapshots of my VMs scripted and my VMs are in a subvolume.
Trying to copy one of the vm snapshots also resulted i