[libvirt-users] Excluding RAW disk from snapshot

[Trey Dockendorf]

On Thu, Aug 2, 2012 at 11:58 AM, Eric Blake <eblake at redhat.com> wrote:
> On 08/02/2012 10:53 AM, Trey Dockendorf wrote:
>
> Did you mean for this to go to the list? Others might benefit from the
> answer.
>
>>>>
>>>> <domainsnapshot>
>>>>   <name>20120802</name>
>>>>   <description>oVirt 3.1 upgrade</description>
>>>>   <disks>
>>>>     <disk name='vda' snapshot='yes' />
>>>>     <disk name='vdb' snapshot='no' />
>>>>   </disks>
>>>> </domainsnapshot>
>>>>
>>>> When I try the snapshot I get this error...
>>>>
>
>> Here's the new XML
>>
>> <domainsnapshot>
>>   <name>20120802</name>
>>   <description>oVirt 3.1 upgrade</description>
>>   <disks>
>>     <disk name='vdb' snapshot='no' />
>>   </disks>
>> </domainsnapshot>
>>
>
> Ah, right - snapshot is a tri-state: 'no', 'internal', and 'external',
> so 'yes' is not a valid state (although currently only 2 of the 3 states
> are supported for qemu: 'no' and 'external').
>
>> Now I get this error
>>
>>
>> # virsh snapshot-create --disk-only dc-vmarchitect dc-vmarchitect_ss.xml
>> error: operation failed: Failed to take snapshot: unknown command:
>> 'snapshot_blkdev'
>
> That's a sign of your qemu being too old to support disk snapshots
> (older qemu only supports system checkpoint internal snapshots).
>
>>
>> I do not know if this could be an issue, but after this wasn't working
>> with libvirt-0.9.4, I did "yum update qemu-img qemu-kvm libvirt" and
>> am now at the versions listed in previous email.  I did not do a full
>> system upgrade or reboot as this is a heavily loaded production
>> system.  Is this the case where the VM is running as the previous
>> version of qemu-kvm ?
>>
>> Thanks
>> - Trey
>>
>
> --
> Eric Blake   eblake at redhat.com    +1-919-301-3266
> Libvirt virtualization library http://libvirt.org
>

Replying back to list, accidently missed reply-all.

Could it be the case that since I upgraded libvirt and qemu while all
the VMs were running, that the VM has to be restarted to take on the
updated version's capability?

If this isn't something yet supported in EL6.3, which I hope it is, is
there any other way to perform a snapshot and exclude a disk aside
from temporarily detaching it from the VM?

Thanks
- Trey