I should have been clearer. you would have a filesystem (ext4, probably.) The challenge would be to retain fs jourmal on migration- a process would be needed to force umount/remount on the target node on migration before bringing up the vm; chances are this can't be done live.How do you write a qcow format directly to raw disk and keep the QCOW addressing?
the presumption here is that only pve hosts have access to the storage; only the host actively accessing the vdisk would normally attempt to actively use it; the rest natually ignore it. Proper lun mapping/masking needs to be followed just as with any other environment; I dont *think* you'd need any further controls.This has to be carefully fenced.
The alternative to this would be to write your own snapshotting mechanism, assuming the back end store has an api, similar to how pve does zfs over iscsi- and then submit it to inclusion into pve