[ovirt-users] Data(Master)

[Greg Padgett]

On 12/01/2015 02:39 PM, Sandvik Agustin wrote:
> Hi users,
>
> I'm using oVirt 3.4 on rhel 6.5 and it's working perfectly, but when i'm
> setting up another Hypervisor and ovirt-engine I accidentally attach my
> working storage "Data(Master)" to my 2nd one, and my problem is i'm unable
> to re-attach it to my first one, is it possible to re-attach it without
> loosing my vm guest disk images? And when I accidentally attach it to my
> 2nd one, It prompt me that "This operation might be unrecoverable and
> distructive" is there a change that my 25 vm guest disk images will be
> erased? God Bless.


Hi Sandvik,

I'm guessing this was iSCSI storage based on the error message.

If so, unfortunately the LVM metadata for the original storage domain will 
have been overwritten due to attaching the domain to the second setup, so 
it can't simply be re-attached to the first.

However, the images are probably still (mostly?) intact as long as the 
storage has been relatively untouched. If you feel it's worthwhile and are 
comfortable getting your hands a little dirty you may be able to recover 
some of the images by finding them on the LUN.

To do this, I'd check your hypervisors' /etc/lvm/archive directories and 
look for an lvm metadata backup as in [1],[2]. You want to look for a VG 
with the UUID of your old master storage domain. The LV names within would 
correspond to your old VM disk image UUIDs.  If you find this (via the 
backup, `pvck`, or even by scouring the first MB or so of the LUN), you 
might be able to recover it via some hints in [1] or [2] (of course 
maintenance/detach the domain from the second hypervisor first).  You can 
then copy the data onto a new storage domain.

Hope that helps,
Greg

[1] 
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Logical_Volume_Manager_Administration/mdatarecover.html

[2] 
http://serverfault.com/questions/223361/how-to-recover-logical-volume-deleted-with-lvremove


> TIA
> Sandvik
>
>
> _______________________________________________
> Users mailing list
> Users at ovirt.org
> http://lists.ovirt.org/mailman/listinfo/users
>