Re: Does XEN have any hot backup/snapshot features or plan?

[zign <zign@hongo.wide.ad.jp>]

Mr Brendan Cully,
Thank you for your fast reply!
LVM + checkpoint sounds reasonable, but there is problem:
if the storage and the MEM checkpoint are not saved in the
very same time, I am not sure if this is a "correct" snapshot.
You mentioned something about the migration hook that can tie
the MEM checkpoint and the LVM snapshot together. Can this
migration hook ensure that there is no "time-shift" between the
MEM and storage?

Brendan Cully 写道:
> On Monday, 06 April 2009 at 08:47, zign wrote:
>   
>> Hello everybody,
>>  My name is Zign and I would like to ask a simple question.
>>  For example, I want to backup my VMs everyday. But I do not
>> want them to be stopped while the backup. For this reason, I can't
>> use a traditional way like:  freeze the VM  -> backup everything ->
>> restore the VM.
>>  So is there any solution for this?
>>     
>
> I don't know of a complete tool, but the parts are all there. xm save
> -c creates a checkpoint of a VM without destroying it, and LVM lets
> you easily snapshot a disk. You can tie them together using the
> external device migration hook in xend -- I think I posted a demo
> script to this list many months ago that does this.
>
> I can't remember whether xm save -c also supports --live in xend, but
> if not it's a trivial change that can reduce the time that the VM is
> paused for backup to almost nothing. The checkpoints may be larger in
> that case, but they can be folded down to simple images afterwards. I
> have a script somewhere around here that does this rewriting, but I
> haven't used it in some time.
>
> You might also think about running your VM on parallax, and saving its
> images there too -- parallax can figure out the deltas between series
> of images for you automatically.
>
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>   


-- 
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Zhao Yue
  Esaki Laboratory,
  Information Physics & Communication Engineering,
  Graduate School of Information Science and Technology,
  The University of Tokyo
Email: zign@hongo.wide.ad.jp
       zign@zign.cn