From mboxrd@z Thu Jan 1 00:00:00 1970 From: zign Subject: Re: Does XEN have any hot backup/snapshot features or plan? Date: Mon, 06 Apr 2009 09:16:40 +0900 Message-ID: <49D949E8.80105@hongo.wide.ad.jp> References: <49D942F6.6030400@hongo.wide.ad.jp> <20090405235450.GD53590@zanzibar.kublai.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <20090405235450.GD53590@zanzibar.kublai.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Brendan Cully Cc: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org Mr Brendan Cully, Thank you for your fast reply! LVM + checkpoint sounds reasonable, but there is problem: if the storage and the MEM checkpoint are not saved in the very same time, I am not sure if this is a "correct" snapshot. You mentioned something about the migration hook that can tie the MEM checkpoint and the LVM snapshot together. Can this migration hook ensure that there is no "time-shift" between the MEM and storage? Brendan Cully =E5=86=99=E9=81=93: > On Monday, 06 April 2009 at 08:47, zign wrote: > =20 >> Hello everybody, >> My name is Zign and I would like to ask a simple question. >> For example, I want to backup my VMs everyday. But I do not >> want them to be stopped while the backup. For this reason, I can't >> use a traditional way like: freeze the VM -> backup everything -> >> restore the VM. >> So is there any solution for this? >> =20 > > I don't know of a complete tool, but the parts are all there. xm save > -c creates a checkpoint of a VM without destroying it, and LVM lets > you easily snapshot a disk. You can tie them together using the > external device migration hook in xend -- I think I posted a demo > script to this list many months ago that does this. > > I can't remember whether xm save -c also supports --live in xend, but > if not it's a trivial change that can reduce the time that the VM is > paused for backup to almost nothing. The checkpoints may be larger in > that case, but they can be folded down to simple images afterwards. I > have a script somewhere around here that does this rewriting, but I > haven't used it in some time. > > You might also think about running your VM on parallax, and saving its > images there too -- parallax can figure out the deltas between series > of images for you automatically. > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xensource.com > http://lists.xensource.com/xen-devel > > =20 --=20 =3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D= -=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D- Zhao Yue Esaki Laboratory, Information Physics & Communication Engineering, Graduate School of Information Science and Technology, The University of Tokyo Email: zign@hongo.wide.ad.jp zign@zign.cn