fix lv removing

templates/backup-vm.j2

@@ -15,6 +15,8 @@ set -euo pipefail
 
 	function delete_snapshots {
 		cleanup_vmmount > /dev/null 2>&1
+		# wait for lazy umount to finish
+		sleep 3
 		for i in $DISKS; do
 			extract_lvm
 			SNAPSHOT="/dev/$VG/backup-$DEVICE"