Re: [Qemu-devel] [RFC] qmp interface for save vmstate to image

[Wenchao Xia]

于 2013-3-15 22:51, Stefan Hajnoczi 写道:
> On Fri, Mar 15, 2013 at 03:24:38PM +0800, Wenchao Xia wrote:
>>    I'd like to add a new way to save vmstate, which will based on the
>> migration thread, but will write contents to block images, instead
>> of fd as stream. Following is the method to add API:
> 
> Hi Wenchao,
> What use cases are there besides saving vmstate to a raw image?
> 
> I'm curious if you're proposing this since there is no "file:" URI or
> because you really want to do things like saving vmstate into a qcow2
> file or over NBD.
> 
> Stefan
> 
Hi, Stefan
  Most used cases would be "raw" and "qcow2", which is flex and can be
chosen by user. In this way, existing block layer feature in qemu can
be used, such as tagging zeros. I haven't check the buffer/cache status
in qemu block layer, but if there is, it can also benefit.
  User can specify "raw" or "qcow2" according to host configuration, If
there is dedicated storage components underlining, he can use "raw" to
skip qemu's block layer.

-- 
Best Regards

Wenchao Xia