From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:46883) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RIgu0-0001cr-Nr for qemu-devel@nongnu.org; Tue, 25 Oct 2011 09:18:49 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RIgtz-0002hk-EI for qemu-devel@nongnu.org; Tue, 25 Oct 2011 09:18:48 -0400 Received: from mx1.redhat.com ([209.132.183.28]:31985) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RIgtz-0002hc-7C for qemu-devel@nongnu.org; Tue, 25 Oct 2011 09:18:47 -0400 Message-ID: <4EA6B730.3040609@redhat.com> Date: Tue, 25 Oct 2011 15:18:40 +0200 From: Dor Laor MIME-Version: 1.0 References: <4EA6ACFE.6090109@redhat.com> <4EA6B41B.3000903@codemonkey.ws> In-Reply-To: <4EA6B41B.3000903@codemonkey.ws> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] KVM call agenda for October 25 Reply-To: dlaor@redhat.com List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: Kevin Wolf , Paolo Bonzini , qemu-devel@nongnu.org, kvm@vger.kernel.org On 10/25/2011 03:05 PM, Anthony Liguori wrote: > On 10/25/2011 07:35 AM, Kevin Wolf wrote: >> Am 24.10.2011 13:35, schrieb Paolo Bonzini: >>> On 10/24/2011 01:04 PM, Juan Quintela wrote: >>>> >>>> Hi >>>> >>>> Please send in any agenda items you are interested in covering. >>> >>> - What's left to merge for 1.0. >> >> I would still like to cache the default cache mode (probably to >> cache=writeback). We don't allow guests to toggle WCE yet which Anthony >> would have liked to see before doing the change. Is it a strict >> requirement? > > I don't see a way around it. If the default mode is cache=writeback, > then we're open to data corruption in any guest where barrier=0. With > guest togglable WCE, it ends up being a guest configuration issue so we > can more or less defer responsibility. > > Do you think it's a good idea to change the default mode w/o guest WCE > toggle support? What's your view about older guests if we change the > default mode? What's your main motivation for wanting to change the > default mode? > > I'd be much more open to changing the default mode to cache=none FWIW > since the risk of data loss there is much, much lower. A bit related to this, it would be nice to mark a VM un-migratable if cache!=none. Juan reports that currently it such VMs are exposed to data integrity issues so we need to fail migrating them automatically. > > Regards, > > Anthony Liguori > >> >> Kevin >> > >