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Re: KVM live block migration: stability, future, docs

 

On 08/07/2012 08:23 PM, Blair Bethwaite wrote:
> Hi Jay,
> 
> On 8 August 2012 06:13, Jay Pipes <jaypipes@xxxxxxxxx> wrote:
>> Why would you find this surprising? I'm just curious...
> 
> The live migration algorithm detailed here:
> http://www.linux-kvm.org/page/Migration, seems to me to indicate that
> only a brief pause should be expected. Indeed, the summary says,
> "Almost unnoticeable guest down time".
> 
> But to the contrary. I tested live-migrate (without block migrate)
> last night using a guest with 8GB RAM (almost fully committed) and
> lost any access/contact with the guest for over 4 minutes - it was
> paused for the duration. Not something I'd want to do to a user's
> web-server on a regular basis...

Sorry, from your original post, I didn't think you were referring to
live migration, but rather just server migration. You had written
"Compared to regular (non-block) live migrate", but I read that as
"Compared to regular migrate" and thought you were referring to the
server migration behaviour that Nova supports... sorry about that!

Best,
-jay


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