Issue


I cannot clean the dangling device mappers.


Environment


OnApp 3.x, 4.x, 5.x, 6.x

Integrated Storage


Resolution


If the disk belongs to an online virtual server, reboot the virtual server to fix the issue. Find which virtual server uses this disk.

If the virtual server is offline, the entries are on one of the compute resources. They can be found with dmsetup ls --tree | grep <<disk_id>> and removed with dmsetup remove.

Example

[root@11.12.13.14 ~]# dmsetup ls --tree | grep asdfasdfasdf12
asdfasdfasdf12 (253:8)
|-3_asdfasdfasdf12 (253:7)
|-2_asdfasdfasdf12 (253:6)
|-1_asdfasdfasdf12 (253:5)
`-0_asdfasdfasdf12 (253:4)
[root@11.12.13.14 ~]# dmsetup remove asdfasdfasdf12
[root@11.12.13.14 ~]# dmsetup remove 0_asdfasdfasdf12
[root@11.12.13.14 ~]# dmsetup remove 1_asdfasdfasdf12
[root@11.12.13.14 ~]# dmsetup remove 2_asdfasdfasdf12
[root@11.12.13.14 ~]# dmsetup remove 3_asdfasdfasdf12
[root@11.12.13.14 ~]#
CODE


Additional Information


The dangling device mapper indicates that there are some orphaned connections on the compute resource for a virtual server disk. They do not cause data loss but can interfere with transactions and backups as the storage may have issues with activating or deactivating the disk.