[sheepdog] Qemu Live Migration and Cache

Bastian Scholz nimrodxx at gmx.de
Fri Jun 8 09:49:30 CEST 2012


Am 2012-06-07 12:07, schrieb Yibin Shen:
> On Thu, Jun 7, 2012 at 5:38 PM, Liu Yuan <namei.unix at gmail.com> 
> wrote:
>> Maybe you refer to object cache?

Yes, sorry, mixed that two...

>> Without object cache, the answer is NO, the data will be known to 
>> the
>> cluster as soon as the request is completely.
>>
>> With object cache enabled, probably 'nope' again, but I am not 100%
>> sure, live migration mechanism from QEMU will issue a flush request 
>> to
>> sheep and block for it, then will migrate memory to other machine. 
>> For
>> the last try with live migration, it did the right thing for me, but
>> you'd better test it with your own. When I have time, I'll try it 
>> again
>> and give you a solid answer.so
> qemu will call sync operation before live migration,(nearly) all 
> dirty
> objects will be
> flushed to sheepdog cluster.

Thanks for your infos.

I am using libvirt with virt-manager on top to manage my virtual
machines. With sheepdog 0.2.4 live migration works without problems
for month.

If the current sheepdog version will work for me, I make some more
migration tests and give a feedback.

Cheers

Bastian




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