From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dor Laor Subject: Re: [Qemu-devel] KVM call agenda for October 25 Date: Tue, 25 Oct 2011 15:18:40 +0200 Message-ID: <4EA6B730.3040609@redhat.com> References: <4EA6ACFE.6090109@redhat.com> <4EA6B41B.3000903@codemonkey.ws> Reply-To: dlaor@redhat.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Kevin Wolf , Paolo Bonzini , qemu-devel@nongnu.org, kvm@vger.kernel.org To: Anthony Liguori Return-path: Received: from mx1.redhat.com ([209.132.183.28]:50076 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756355Ab1JYNSr (ORCPT ); Tue, 25 Oct 2011 09:18:47 -0400 In-Reply-To: <4EA6B41B.3000903@codemonkey.ws> Sender: kvm-owner@vger.kernel.org List-ID: 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 >> > >