Re: [Qemu-devel] [PATCH 4/6] snapshot: implemention of common API to take snapshots

[Eric Blake]

On 12/17/2012 02:58 AM, Dietmar Maurer wrote:
>>>>> Seems this makes it impossible to use external commands to make
>>>> snapshots?
>>>>>
>>>>     what command? can you tip more about the case?
>>>
>>> For example, nexenta storage provides an API to create snapshots. We
>>> want to use that. Another example would be to use lvcreate to create lvm
>> snapshots.
>>>
>>    I am not familar with those tools, Patch 5 and 6 provides hmp and qmp API,
>> hope you can enlight more what is  missing if it can't work with external 
>> tool.
> 
> We need the ability to create snapshots with external tools - your patch does 
> not support that.
> I think that is a major drawback.

I think the ability to create snapshots with external tools is going to
require asynchronous snapshots, where the work is divided into several
phases.  You'll need qemu to prepare for the snapshot, then the external
tools to create the snapshot, then resume qemu with possibly different
file names as a result of the snapshot being created.  I'm certainly
interested in seeing what you come up with, and how libvirt will be able
to interact with it for external tool snapshots.

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

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