This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigF9139496C7A82FD9477CDE29 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 06/28/2012 07:07 AM, Dave Allan wrote:
On Thu, Jun 28, 2012 at 06:34:25AM -0400, Itamar Heim wrote:
On 06/28/2012 04:40 AM, Winfried de Heiden wrote:
Hi all,
It seems live snapshot is available in the Fedora 17 qemu-kvm. On my laptop with kvm, virt-manager, libvirt, virsh etc. I created a virtua= l machine and tried to make a live snapshot:
virsh # snapshot-create RHEL55_NTP Domain snapshot 1340871802 created
That's a system-checkpoint snapshot, because you didn't use --disk-only. When you say 'live snapshot' were you intending the fast operation of just a disk snapshot (via the 'transaction' or 'blockdev-snapshot-sync' monitor command) or the slow operation of a checkpoint (via the 'savevm' monitor command)?
[root@kvm ~]# rpm -qf `which qemu-kvm` qemu-system-x86-1.0-17.fc17.x86_64
[wdh@laptop-winfried ~]$ rpm -qf `which qemu-kvm` qemu-system-x86-1.0-17.fc17.x86_64
This qemu does not support the 'transaction' monitor command, so libvirt has to fall back to the non-atomic 'blockdev-snapshot-sync', or else give up because of missing functionality.
dave - who can help us elaborate on this libvirt error: reuse is not supported with this QEMU binary
this is the relevant error coming from libvirt. maybe fedora 17 qemu-kvm does not have live snapshot support?
Thread-306::ERROR::2012-06-27 12:46:40,178::libvirtvm::1782::vm.Vm::(snapshot) vmId=3D`ef978066-09c8-40aa-8e0b-4accfacc15bd`::Unable to take snapsh=
ot
Traceback (most recent call last): File "/usr/share/vdsm/libvirtvm.py", line 1780, in snapshot libvirt.VIR_DOMAIN_SNAPSHOT_CREATE_REUSE_EXT))
OK, so this is a case of VDSM driving a different use of the API than what you did with your virsh command line. VDSM is attempting to do the equivalent of 'virsh snapshot-create --disk-only --reuse-ext', but because your qemu doesn't support the 'transaction' command, libvirt can't make qemu do what VDSM wants. Basically, the 'blockdev-snapshot-sync' command in qemu 1.0 lacks the ability to reuse qcow2 metadata already present in the file pre-created by VDSM; this wasn't added until the 'transaction' command of qemu 1.1. --=20 Eric Blake eblake@redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --------------enigF9139496C7A82FD9477CDE29 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQEcBAEBCAAGBQJP7FoYAAoJEKeha0olJ0Nqlp4IAInfMKgj+mZ8KaiMSKKTNXiq Fj3oiRvTthgRh7yev8UumAQVSTM/MMCJ8AU81OkjzQlKK+p+E8PI0XYV5qqS6m2z PvUxtGE1X+IZqwaG6KETTh8zHX1LxZ1vEJ9IUmyngbklJWSjPGPbkZcspBX0TP2E v3t4ElbxTA6mHIjIMFj9YD9IgFkd0V/Qf3qsZrCk/SYIZlBTowzevRF+DL8LJjoa FKvvSkDXFriRhjJrvXv0AGkqXjmGqWFAo+2Iz7LmcGnwzK8zPJqG1Mt8Z9rBdx9h Uiud2GgKarT2pImkyS8OO68sE9GDOxWnQk9VOYiSZW9xmLO+sO2NTvEklCB5ZO8= =Hgxs -----END PGP SIGNATURE----- --------------enigF9139496C7A82FD9477CDE29--