Am Montag, den 15.10.2012, 13:11 +0200 schrieb Kevin Wolf: > Am 12.10.2012 10:53, schrieb 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? > > Yes, in theory that should be harmless and even produce a correct copy > of the snapshot.
Good to know, thanks. > > > 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. > > So no internal snapshots are involved at all with this new image? No. I just checked again: no internal snapshot are currently present nor have been added/removed in the past. > I'm > asking because in the past non-reproducible failures were reported with > snapshots, but I'm not aware of any case that didn't use snapshots. > > Any other non-default feature that you used, like compression? No, we either create the qcows by hand using: qemu-img create -f qcow2 kvm-0XY_01.qcow2 30G or (usually) using libvirt: virsh vol-create $pool $diskfile where $diskfile points to a xml like this: <volume> <name>${diskfilename}</name> <allocation>0</allocation> <capacity unit="G">${kvmsize}.qcow2</capacity> <target> <format type='qcow2'/> <permissions> <owner>0</owner> <group>3000</group> <mode>0660</mode> </permissions> </target> </volume> and $pool references a directory-based storage pool. -- stepping stone GmbH Neufeldstrasse 9 CH-3012 Bern Telefon: +41 31 332 53 63 www.stepping-stone.ch tiziano.muel...@stepping-stone.ch