WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-users

Re: [Xen-users] Live migration: 2500ms downtime

To: "Luciano Rocha" <strange@xxxxxxxxxxxxx>
Subject: Re: [Xen-users] Live migration: 2500ms downtime
From: "Marconi Rivello" <marconirivello@xxxxxxxxx>
Date: Sat, 11 Aug 2007 00:57:48 -0300
Cc: xen-users@xxxxxxxxxxxxxxxxxxx
Delivery-date: Fri, 10 Aug 2007 20:58:17 -0700
Dkim-signature: a=rsa-sha1; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:references; b=lBXP1JF5Xql46ock5YVtESJ9o9/i3AB+TgnYdlnx3X2HcJ0sKzWERUdi1gl704za2NFRIVftijFX3wfJIMPLJixZ/f0t73huEbEss29Ykmbg+SGkEEnrWYxz88lKsXP4XxPiwq/EssGfeAFCC5pxfngA32Eld1LMAInE375taps=
Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:references; b=CV7GYXlxFuMzEcctkJyRXR1ma+/Bbu2lBksmXj+5NGQtiKIi+HZYeRbg4SDRb+S6B6HLK5GXVEClq+q+k3a8vd9WaSzBPOJ8k2lvSgzXV9IORSVzLvyKlHN4pDhqOi2IhrzWTJ2SOlpg3j15oHI0waM4QsSApv/Fm7GOxT9Kz10=
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <20070810203139.GA4302@xxxxxxxxxxxxxxxxxxxxxx>
List-help: <mailto:xen-users-request@lists.xensource.com?subject=help>
List-id: Xen user discussion <xen-users.lists.xensource.com>
List-post: <mailto:xen-users@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=unsubscribe>
References: <bd15b9d50708100415h72b7036ek5d248f1ff1bbe308@xxxxxxxxxxxxxx> <f9264670708100515te52ef07l9e5e86e925b58224@xxxxxxxxxxxxxx> <bd15b9d50708100721k41309835u8cb845d017882b19@xxxxxxxxxxxxxx> <f9264670708100808g7d54ed83m3537c80888fb64ba@xxxxxxxxxxxxxx> <bd15b9d50708100842l7c4486famff66d9a516ba9162@xxxxxxxxxxxxxx> <20070810162307.GA941@xxxxxxxxxxxxxxxxxxxxxx> <bd15b9d50708101018r22b5732fp6bc94508685688b8@xxxxxxxxxxxxxx> <20070810203139.GA4302@xxxxxxxxxxxxxxxxxxxxxx>
Sender: xen-users-bounces@xxxxxxxxxxxxxxxxxxx


On 8/10/07, Luciano Rocha <strange@xxxxxxxxxxxxx> wrote:
On Fri, Aug 10, 2007 at 02:18:53PM -0300, Marconi Rivello wrote:
> Hi, Luciano.
>
> On 8/10/07, Luciano Rocha <strange@xxxxxxxxxxxxx> wrote:
> >
> > On Fri, Aug 10, 2007 at 12:42:08PM -0300, Marconi Rivello wrote:
> > > Another issue that I described on a previous email (which,
> > unfortunately,
> > > didn't get any replies) is that this downtime increases to more than 20
> > > seconds if I set the domU's memory to 512MB (the maxmem set is 1024MB).
> > I
> > > repeated the test successively, from one side to the other, with mem set
> > to
> > > 512 and 1024, and the result was always the same. Around 3s with mem =
> > > maxmem, and around 24s with mem=512 and maxmem=1024.
> > >
> >
> > You are using the option --live to migrate, aren't you?
>
>
> Yes, I am. :)

Oh. Well, then, could you try without? :)

I could, but what I'm whining :) about is to have a period of unresponsiveness of a couple of seconds, instead of a tenth of a second. If I do a stop-copy-restart migration it will be even longer.

Also, try the reverse. Ping an outside host in the domU.

I will. In fact, I will try all the monitoring suggestions (from you and the others). Inside domU, outside, third machine, ICMP, ARP...

> Even if I weren't, it would make sense to expect a lower downtime (or the
> same downtime) by reducing the domU memory. But it takes longer if I reduce
> the domU's memory.

That is odd. Is the Dom0 memory the same (ie., fixed)?

> Would you happen to have any ideas on why it behaves like that?

No idea. I might expect a longer migration time for a machine with a
very active working set, but not a much longer downtime. That should be
only a freeze, final sync, and resume on the other side.

--
lfr
0/0

_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users



I would like to thank everyone who contributed with ideas. It was very helpful. Unfortunately, I will be gone for the next week on a training, and will only be able to further investigate when I get back to work. When I do, I will do some more tests and post what I find out or not.

Thanks again,
Marconi.
_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users