[Users] Restoring Virtual Machines

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hi, in the process of testing ovirt some questions:
1. If you are upgrading ovirt we erased the database postgress, whether it
is possible to restore the list of virtual machines without having to
restore the database from the dump? Take a virtual machine working on the
nodes.
2. Is it possible to manage virtual machines through the cli?
3. Is it possible to arrange a backup of virtual machines without
interruption of its performance?