In our old 3.4 ovirt, I know I've migrated storage on live VMs and everything seemed to work. However on 3.6.6, I tried this and I saw the warning about moving storage on a live VM (it wasn't doing much of anything) and I went ahead and migrated the storage from one storage domain to another. But when it was through, even though the VM was still alive, when I tried to write to a virtual disk that was part of the move, it paused the VM saying there wasn't enough storage. I could unpause the VM, but in a few seconds, with things writing to the virtual disk, again it was paused with the same out of space message. Vdsm logs showed the enospc return code... so it made sense, it's just that the VM shows plenty of storage there. Once I rebooted the VM, everything went back to normal. So is moving storage for a live VM not supported? I guess we got lucky in our 3.4 system (?)