From mboxrd@z Thu Jan 1 00:00:00 1970 From: Olaf Hering Subject: Re: Strange (???) xl behavior for save, migrate and migrate-receive Date: Mon, 17 Oct 2011 21:12:05 +0200 Message-ID: <20111017191205.GA16667@aepfle.de> References: <20111017174036.GD29445@router-fw-old.local.net-space.pl> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Return-path: Content-Disposition: inline In-Reply-To: <20111017174036.GD29445@router-fw-old.local.net-space.pl> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Daniel Kiper Cc: jeremy@goop.org, xen-devel@lists.xensource.com, konrad.wilk@oracle.com, ian.jackson@eu.citrix.com, v.tolstov@selfip.ru, ian.campbell@eu.citrix.com List-Id: xen-devel@lists.xenproject.org On Mon, Oct 17, Daniel Kiper wrote: > During work on memory hotplug for Xen I have received some notices > that it breaks machine migration. I had some time and I done some > tests a few days ago. It looks that source of this problem is > xl command itself. I discovered that generic save/restore mechanism > is used for machine migration. xl save store machine config which > was used at machine startup with current machine state. It means > that it does not take into account any config changes which were made > during machine run. This behavior does not allow migrating domain, > on which memory hotplug was used, to restore on destination host > because current size of memory allocated for machine is larger than > size of memory allocated at startup by memory option. Yes, it is > memory option not maxmem option. However, it is not important here > because I think that generic behavior of xl save, migrate and migrate-receive > should be changed (fix for memory hotplug case is workaround for the > generic problem which will return sooner or later). I think that xl save, > migrate and migrate-receive should use current machine state and __CURRENT__ > config (from xenstore ???) to do their tasks. However, I am aware that > this change could have large impact on current users. That is why I decided > to ask you about your opinion and suggested solutions in that case > (in general not memory hotplug only). Its easy to implement in xl by throwing some xenstore watches into the code. http://lists.xensource.com/archives/html/xen-devel/2011-10/msg00778.html Olaf