From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=36844 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1P8CCS-0001NJ-4H for qemu-devel@nongnu.org; Tue, 19 Oct 2010 09:26:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1P8BrB-0006Fp-51 for qemu-devel@nongnu.org; Tue, 19 Oct 2010 09:04:04 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60960) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1P8BrA-0006Fl-UV for qemu-devel@nongnu.org; Tue, 19 Oct 2010 09:03:57 -0400 Message-ID: <4CBD9736.2060902@redhat.com> Date: Tue, 19 Oct 2010 15:03:50 +0200 From: Avi Kivity MIME-Version: 1.0 Subject: Re: [Qemu-devel] Re: KVM call agenda for Oct 19 References: <20101019021117.GI25455@sequoia.sous-sol.org> <4CBD93B8.9070002@redhat.com> <4CBD955E.8060909@redhat.com> <4CBD960D.8020806@redhat.com> In-Reply-To: <4CBD960D.8020806@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: dlaor@redhat.com Cc: chrisw@redhat.com, kvm@vger.kernel.org, Juan Quintela , qemu-devel@nongnu.org, Chris Wright , Ayal Baron , "Venkateswararao Jujjuri (JV)" On 10/19/2010 02:58 PM, Dor Laor wrote: > On 10/19/2010 02:55 PM, Avi Kivity wrote: >> On 10/19/2010 02:48 PM, 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? >>> - 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. >> >> Third option, make the freeze path management -> qemu -> virtio-blk -> >> guest kernel -> file systems. The advantage is that it's easy to >> associate file systems with a block device this way. > > OTH the userspace freeze path already exist and now you create another > path. I guess we would still have a userspace daemon; instead of talking to virtio-serial it talks to virtio-blk. So: management -> qemu -> virtio-blk -> guest driver -> kernel fs resolver -> daemon -> apps Yuck. > What about FS that span over LVM with multiple drives? IDE/SCSI? Good points. -- error compiling committee.c: too many arguments to function