From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: [Qemu-devel] KVM call agenda for October 25 Date: Tue, 25 Oct 2011 08:28:29 -0500 Message-ID: <4EA6B97D.7050002@codemonkey.ws> References: <4EA6ACFE.6090109@redhat.com> <4EA6B41B.3000903@codemonkey.ws> <4EA6B730.3040609@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: dlaor@redhat.com Return-path: Received: from mail-gx0-f174.google.com ([209.85.161.174]:41367 "EHLO mail-gx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933399Ab1JYN2d (ORCPT ); Tue, 25 Oct 2011 09:28:33 -0400 Received: by ggnb1 with SMTP id b1so472793ggn.19 for ; Tue, 25 Oct 2011 06:28:32 -0700 (PDT) In-Reply-To: <4EA6B730.3040609@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 10/25/2011 08:18 AM, Dor Laor wrote: > 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. That's not correct. cache!=none is perfectly safe *if* you have coherent shared storage. Regards, Anthony Liguori > >> >> Regards, >> >> Anthony Liguori >> >>> >>> Kevin >>> >> >> > >