Re: best way to create a snapshot of a running vm ?
On Mon, Nov 30, 2015 at 04:34:14PM +0100, Lentes, Bernd wrote: > Stefan wrote: > > > > > Hi Bernd, > > qemu-img cannot be used on the disk image when the VM is running. > > Please use virsh, it communicates with the running QEMU process and > > ensures that the snapshot is crash-consistent. > > > > Hi Stefan, > > thanks for your answer. > > i read that virsh uses internally qemu-img > (http://serverfault.com/questions/692435/qemu-img-snapshot-on-live-vm). > Is that true ? It's false in the general case. While the VM is running libvirt will use the QEMU monitor to communicate with the QEMU process instead of using qemu-img. While the VM is shut down libvirt can use qemu-img safely. The reason why qemu-img isn't safe is that the image file might be written to by the running VM at the same time as qemu-img reads/writes it. This can corrupt image files. Stefan signature.asc Description: PGP signature
RE: best way to create a snapshot of a running vm ?
Stefan wrote: > > Hi Bernd, > qemu-img cannot be used on the disk image when the VM is running. > Please use virsh, it communicates with the running QEMU process and > ensures that the snapshot is crash-consistent. > Hi Stefan, thanks for your answer. i read that virsh uses internally qemu-img (http://serverfault.com/questions/692435/qemu-img-snapshot-on-live-vm). Is that true ? Bernd Helmholtz Zentrum Muenchen Deutsches Forschungszentrum fuer Gesundheit und Umwelt (GmbH) Ingolstaedter Landstr. 1 85764 Neuherberg www.helmholtz-muenchen.de Aufsichtsratsvorsitzende: MinDir'in Baerbel Brumme-Bothe Geschaeftsfuehrer: Prof. Dr. Guenther Wess, Dr. Nikolaus Blum, Dr. Alfons Enhsen Registergericht: Amtsgericht Muenchen HRB 6466 USt-IdNr: DE 129521671 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: best way to create a snapshot of a running vm ?
On Mon, Nov 30, 2015 at 12:36:56AM +0100, Lentes, Bernd wrote: > what is the best way to create a snapshot of a running vm ? qemu-img or virsh > ? > I#d like to create a snapshot which is copied afterwards by other means, e.g. > by a network based backup software. Hi Bernd, qemu-img cannot be used on the disk image when the VM is running. Please use virsh, it communicates with the running QEMU process and ensures that the snapshot is crash-consistent. Stefan signature.asc Description: PGP signature
