[Users] Restoring Virtual Machines

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?