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-devel

[Xen-devel] Xen 3.4.1 and QCOW - sparse backing file support gone foreve

To: xen-devel@xxxxxxxxxxxxxxxxxxx
Subject: [Xen-devel] Xen 3.4.1 and QCOW - sparse backing file support gone forever?
From: Martin Troester <TroyMcClure@xxxxxx>
Date: Thu, 24 Sep 2009 22:43:10 +0200
Delivery-date: Thu, 24 Sep 2009 13:44:04 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Thunderbird 2.0.0.23 (X11/20090817)
Hi,

I'd like to get some hints on using or migrating QCOW images with sparse
backing files.

In February, I posted a question about this and got some hints by Ian
which generally state this support was removed/disabled due to a
possible security issue. For the full thread, please see the post at
http://lists.xensource.com/archives/html/xen-devel/2009-02/msg00150.html

So with Xen 3.4.1 being released already, it seems like I am stuck now
with my chosen approach of having a qcow file which points to another
(non-raw) qcow backing file. This does not boot, everything looks as in
the February Xen 3.3 posting.

Ian, these comments from your last response particularly are of interest
to me:
So I `fixed' this by making all backing files of cow images always be
treated as raw images.  (In upstream this is being fixed by adding
more metadata to the data format but the exact syntax is still
settling down and this change comes too late for Xen 3.3.)
Can you or some qemu developer reading this please explain if this code
actually made it into 3.4.1, and if yes, how I would migrate my existing
files to contain this "more metadata" to be working again?

If that's not in, is there any plan how to deal with scenarios like
mine? Especially, is there way to convert my images to some usable
format for not having to stick to Xen 3.2.1? Or is it just too exotic so
that I throw everything away and think of something else? (I am still
thinking that stacking qcow images is not the most stupid thing to do...)

Thanks for any support and hints on this topic!

Regards,
Martin

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

<Prev in Thread] Current Thread [Next in Thread>