libvirt users - Jan 2014 - Re: how to detect if qemu supports live disk snapshot

>
>
> >
> > So, if I'm not mistaken, looks like the only way to test for the
support
> in QEMU is to actually
> > request a snapshot and see what happens.
> > Is this right?
>
> Unfortunately true for the moment.
>
Hi, does this command can help with you?
  virsh qemu-monitor-command vmname  --hmp 'help' | grep snapshot_blkdev

On 01/14/2014 08:13 PM, Gao Yongwei wrote:
>>
>>
>>>
>>> So, if I'm not mistaken, looks like the only way to test for
the support
>> in QEMU is to actually
>>> request a snapshot and see what happens.
>>> Is this right?
>>
>> Unfortunately true for the moment.
>>
> Hi, does this command can help with you?
>   virsh qemu-monitor-command vmname  --hmp 'help' | grep
snapshot_blkdev
This would work for current versions of qemu, but may not work in the
future (as HMP does not guarantee stable output) - parsing QMP output
would be more reliable.  Furthermore, the 'qemu-monitor-command' is
intentionally unsupported, although this particular use is safe because
it doesn't change guest state behind libvirt's back.


-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

>
> This would work for current versions of qemu, but may not work in the
> future (as HMP does not guarantee stable output) - parsing QMP output
> would be more reliable.  Furthermore, the 'qemu-monitor-command' is
> intentionally unsupported, although this particular use is safe because
> it doesn't change guest state behind libvirt's back.
>
> soga, thanks, :-)