I followed these instructions on a fresh Buster install and this line:
Whole output here: https://pastebin.com/3dUNLFJt
Do you have any hint on what could be expected, as a block device number 22?
This is cat /etc/fstab:
and ls -l /dev/block:
I understand OMV is meant to work with a data partition which is distinct from the root fs, can you figure if the above error is related? I'd like to rule out other issues before reallocating the storage.