I have scheduled daily backups((CIFS)) for containers, today I got following error via mail
200: 2019-11-01 00:00:02 INFO: Starting Backup of VM 200 (lxc)
200: 2019-11-01 00:00:02 INFO: status = running
200: 2019-11-01 00:00:02 INFO: CT Name: CT200
200: 2019-11-01 00:00:02 INFO: backup mode: snapshot
200: 2019-11-01 00:00:02 INFO: ionice priority: 7
200: 2019-11-01 00:00:02 INFO: create storage snapshot 'vzdump'
200: 2019-11-01 00:00:02 ERROR: Backup of VM 200 failed - lvcreate snapshot 'pve/snap_vm-200-disk-0_vzdump' error: Logical Volume "snap_vm-200-disk-0_vzdump" already exists in volume group "pve"
200: 2019-11-01 00:00:02 INFO: Starting Backup of VM 200 (lxc)
200: 2019-11-01 00:00:02 INFO: status = running
200: 2019-11-01 00:00:02 INFO: CT Name: CT200
200: 2019-11-01 00:00:02 INFO: backup mode: snapshot
200: 2019-11-01 00:00:02 INFO: ionice priority: 7
200: 2019-11-01 00:00:02 INFO: create storage snapshot 'vzdump'
200: 2019-11-01 00:00:02 ERROR: Backup of VM 200 failed - lvcreate snapshot 'pve/snap_vm-200-disk-0_vzdump' error: Logical Volume "snap_vm-200-disk-0_vzdump" already exists in volume group "pve"