It is always a good idea to back up the last few OVA (or UTM) files on an external disk. If your host has problems, those OVA files can be run on another host.
If you encounter problems with the disk, it is recommended to boot with “Recovery Mode”, and repairing it.
umount -v /dev/sdb1
umount -v /dev/sdb2
fsck -y -f /dev/sdb1
fsck -y -f /dev/sdb2