herewith one command that will hit your instance in openvz backing them all up and bring them to their current state.
root@google vm:~# vzlist -a | awk '{print $1}' | grep -v CTID | xargs -i vzdump --compress --dumpdir /data/external_drive/backup_openvz --stop {};
after this you can send them out to anyplace you want and deploy them anywhere you want in openvz environment like taking snapshot in amazon webservices