Re: [Qemu-devel] Silent filesystem/qcow2 corruptions with qemu-kvm-1.0 and 1.1.1

[Tiziano Müller]

Am Freitag, den 12.10.2012, 10:33 +0200 schrieb Stefan Hajnoczi:
> On Thu, Oct 11, 2012 at 03:33:23PM +0200, Tiziano Müller wrote:
> > Checking the image using `qemu-img check` then gives something like
> > this:
> > 
> > ERROR OFLAG_COPIED: offset=3bc30000 refcount=1
> > ERROR offset=c7e331: Cluster is not properly aligned; L2 entry
> > corrupted.
> 
> Is any other program accessing the qcow2 image on the host while the VM
> is running?

> For example, are you running qemu-img on the image while the VM is
> running?

On some VMs we tried to extract filesystem snapshots at runtime:

  qemu-img convert -s snapshot-id original.qcow2 snapshot.qcow2

(yes, that's not consistent, we're switching to external snapshots).
But that should open the image read-only, right?

Other operations where the qemu-monitor-commands "savevm" and "delvm". 

Although: we created a new qcow2 and even in that the filesystem got
corrupted without any of the above actions. So we're pretty confident
that those operations are not the sole cause.


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