If both type and vmid is defined we don't need to list the current snapshots, we simply can derive the single backup group from that and let the PBS client handle the rest. Should be a not so small speedup for most setups using PBS backup and pruning configured on PVE side, as vzdump calls this separately for every vmid on backup jobs with multiple guests included. Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>