We are currently sitting on a not really working backup solution. oVirt 4.5.x has constant
issues removing snapshots, same like OP. vProtect with Snapshots has issues with oVirt
deleting snapshots. vProtect 5.1 has broken CBT with oVirt 4.5.x.
vProtect support tells us that the snapshot issues is in oVirt (true) and CBT is a preview
feature not really supported. So currently vProtect 5.1 and oVirt 4.5 is a no go solution.
We are thinking going to xcp-ng due to constant issues with oVirt and or vProtect.