[SOLVED] run mdadm --zero-superblock before removing guest vdi

Valerio Pachera

Active Member
Aug 19, 2016
Hi, this is a corner case.
I have a proxmox 5 installation using lvm-thin on top of a raid 1 software raid (mdadm).
One of my guests was OpenMediaValut (a nas sitribution) that I was testing.
The guest has 3 vdi, two of them were used to build a raid 1 volume (inside the guest).

I was not using this guest since long so I chose to remove it.
I also made some more maintenance to my host, so I rebooted it a couple of times and lastly I run apt full-upgrade.
During the upgrade apt was complaining abount a raid volume not mentioned in /etc/mdadm/mdadm.conf.
By mdadm --examine --scan I found out a /dev/md127 composed of the two OMV vdi.
The guest (vm id 118) was not on proxmox anymore but 2 of its logical volume were till alive.
I guess proxmox wan't able to remove the logical volumes because they were kept busy by mdadm (of the host).
BTW, I has to stop /dev/md127 and run mdadm --zero-superblock on the the two logical volumes.

Usually you don't run mdadm on guests unless for testing as I was doing.
I don't know if proxmox may be able to handle such corner case.

Hope this may help somebody avoiding mistakes.


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