From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: [Qemu-devel] Re: KVM call agenda for Oct 19 Date: Tue, 19 Oct 2010 08:22:15 -0500 Message-ID: <4CBD9B87.9010008@codemonkey.ws> References: <20101019021117.GI25455@sequoia.sous-sol.org> <4CBD93B8.9070002@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Chris Wright , Juan Quintela , chrisw@redhat.com, "Venkateswararao Jujjuri (JV)" , qemu-devel@nongnu.org, kvm@vger.kernel.org, Ayal Baron To: dlaor@redhat.com Return-path: Received: from mail-yx0-f174.google.com ([209.85.213.174]:47785 "EHLO mail-yx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758637Ab0JSNWU (ORCPT ); Tue, 19 Oct 2010 09:22:20 -0400 Received: by yxm8 with SMTP id 8so1124443yxm.19 for ; Tue, 19 Oct 2010 06:22:19 -0700 (PDT) In-Reply-To: <4CBD93B8.9070002@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 10/19/2010 07:48 AM, Dor Laor wrote: > On 10/19/2010 04:11 AM, Chris Wright wrote: >> * Juan Quintela (quintela@redhat.com) wrote: >>> >>> Please send in any agenda items you are interested in covering. >> >> - 0.13.X -stable handoff >> - 0.14 planning >> - threadlet work >> - virtfs proposals >> > > - Live snapshots > - We were asked to add this feature for external qcow2 > images. Will simple approach of fsync + tracking each requested > backing file (it can be per vDisk) and re-open the new image would > be accepted? I had assumed that this would involve: qemu -hda windows.img (qemu) snapshot ide0-disk0 snap0.img 1) create snap0.img internally by doing the equivalent of `qemu-img create -f qcow2 -b windows.img snap0.img' 2) bdrv_flush('ide0-disk0') 3) bdrv_open(snap0.img) 4) bdrv_close(windows.img) 5) rename('windows.img', 'windows.img.tmp') 6) rename('snap0.img', 'windows.img') 7) rename('windows.img.tmp', 'snap0.img') Regards, Anthony Liguori > - Integration with FS freeze for consistent guest app snapshot > Many apps do not sync their ram state to disk correctly or frequent > enough. Physical world backup software calls fs freeze on xfs and > VSS for windows to make the backup consistent. > In order to integrated this with live snapshots we need a guest > agent to trigger the guest fs freeze. > We can either have qemu communicate with the agent directly through > virtio-serial or have a mgmt daemon use virtio-serial to > communicate with the guest in addition to QMP messages about the > live snapshot state. > Preferences? The first solution complicates qemu while the second > complicates mgmt. > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html