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] migrating ballooned domains

To: David Becker <becker@xxxxxxxxxxx>
Subject: Re: [Xen-users] migrating ballooned domains
From: "M.A. Williamson" <maw48@xxxxxxxxx>
Date: 21 Mar 2006 18:16:31 +0000
Cc: xen-users@xxxxxxxxxxxxxxxxxxx
Delivery-date: Tue, 21 Mar 2006 18:18:04 +0000
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <20060321180639.GF18059@xxxxxxxxxxx>
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: <20060321180639.GF18059@xxxxxxxxxxx>
Reply-to: mark.williamson@xxxxxxxxxxxx
Sender: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
This error is due to the destination xend trying to create a domain
of the original size, rather than allocating just the shurnk size.
I can successfully migrate a domain created small enough to fit on the
destination host at the domain's original size.

Is this a fundamental issue, or just a bug in xend?   I'm still scarred
from the last time I hunted through the xend python so I have not actually
tried to run this down this myself.

It's a feature ;-)

OK, so maybe not.  IIRC, the issue was something like:

origin machine retrieves domain size from Xen, Xen reports original memory allocation

origin machine tries to reserve that amount of space on destination

bam

There've been mails about this in the past, with some discussion as to what needed doing. I'd say it should be possible to fix this at the control plane - I don' think it's a terribly fundamental issue, and it is one we've occasionally run across before.

If we support migrating ballooned domains, I guess we *might* have to prevent the domain from ballooning itself up whilst it's being migrated - otherwise it could break the migration process. This could probably be done by just lowering its memory limit whilst the pre-copy phase is taking place.

HTH

Cheers,
Mark

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

<Prev in Thread] Current Thread [Next in Thread>