WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-users

RE: [Xen-users] Backup; mount domU FS RO?

To: <Xen-users@xxxxxxxxxxxxxxxxxxx>
Subject: RE: [Xen-users] Backup; mount domU FS RO?
From: "Daniel Goertzen" <daniel.goertzen@xxxxxxxxxxx>
Date: Mon, 19 Dec 2005 13:18:00 -0600
Delivery-date: Mon, 19 Dec 2005 19:20:45 +0000
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <20051219114352.GA10835@xxxxxxxxxxxxxxx>
List-help: <mailto:xen-users-request@lists.xensource.com?subject=help>
List-id: Xen user discussion <xen-users.lists.xensource.com>
List-post: <mailto:xen-users@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: AcYEkYx2JA6r9TBPT2qWsnwJwsLwmQAPlAlg
 On Mon, Dec 19, 2005 at 08:04:50AM +0100, als@xxxxxxxxxxxxxxx wrote:
[...]
> A better approach is to use LVM and snapshots. Use LVM logical volumes 
> as "disks" for your DomU (if you aren't already doing this), create 
> snapshots for your backups, mount the snapshots and backup _those_.
[...]
> 
> I'm currently using this to backup our production DomU systems from 
> the Dom0 and it works very well.

How do you assure that domU's filesystem is in a consistent state when the
snapshot is being taken in dom0?
Also, which distro+kernel do you use?

Marcin



You won't know, but I bet it works most of the time.  While taking a
snapshot the LVM system will lock the VFS to assure consistency.  In the
above scenario the dom0 has no way of locking the domU's VFS, therefore
consistency is NOT assured.  The LVM user above should be creating the
snapshot from the same domU that has that logical volume mounted... At this
point you're probably better off with another solution.

Dan.


_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users