[root@ov-engine ~]# tail -f /var/log/ovirt-engine/engine.log | grep ERROR grepping error is ok, but it does not show the reason for the failure, which will probably be on the vdsm host (you can use flow_id 9b2283fe-37cc-436c-89df-37c81abcb2e1 to find the correct file Need to see the underlying error causing: VDSGenericException: VDSErrorException: Failed to SnapshotVDS, error = Snapshot failed, code = 48
Using unlock_entity.sh -t all sets the status back to 1 (confirmed in DB) and then trying to create does not change it back to illegal, but trying to delete that snapshot fails and sets it back to 4. I see, can you share the removal failure log (similar information as requested above)
regarding backup, I don't have a good answer, hopefully someone else has suggestions