After digging around and finding a bit of info about viodiskcache - I understand that if the user enable it - then the VM cannot be live migrated.
Umm, unless the op decides to do a live migration including changing storage - I don't understand why the live migration is disabled. If the VM will only be live migrated between nodes, then the storage is the same, nothing is saved locally on the node's hard disk, so what is the reason to disable live migration?
I think the issue is synchronizing the host buffer cache on different hosts. Each kernel thinks it
control storage, while storage is accessed by two hosts at the same time.
I'm sure Kevin or Eric can provide a better answer.