On 04/14/2014 06:52 AM, Kevin Wolf wrote: > Am 14.04.2014 um 12:33 hat Pavel Lisý geschrieben: >> Hello >> >> I've made virtual guest on Fedora 20 (x86_64) within qcow2 image file >> but after migration to CentOS 6.5 I've got this error: >> >> qemu-kvm: -drive >> file=/var/lib/libvirt/images/questfile.qcow2,if=none,id=drive-virtio-disk0,format=qcow2: >> 'drive-virtio-disk0' uses a qcow2 feature which is not supported by this >> qemu version: QCOW version 3 >> >> similar error I've got for qemu-img: >> # qemu-img info /var/lib/libvirt/images/questfile.qcow2 >> 'image' uses a qcow2 feature which is not supported by this qemu version: >> QCOW version 3 >> >> On F20 it returns: >> # qemu-img info /var/lib/libvirt/images/questfile.qcow2 >> image: /var/lib/libvirt/images/rhel6.qcow2 >> file format: qcow2 >> virtual size: 32G (34359738368 bytes) >> disk size: 4.7G >> cluster_size: 65536 >> >> >> Have I missed something? >> >> Is it qcow2 on Fedora different from CentOS6? Is there any possibility >> (on Fedora 20) to convert it to backward compatible format? > > qemu versions starting with 1.1 can use new qcow2 features which require > an incompatible on-disk format. Between version 1.1 and 1.6, they needed > to be specified explicitly during image creation, like this: > > qemu-img create -f qcow2 -o compat=1.1 test.qcow2 8G > > Starting with qemu 1.7, compat=1.1 became the default, so that newly > created images can't be read by older qemu versions by default. If you > need to read them in older version, you now need to be explicit about > using the old format: > > qemu-img create -f qcow2 -o compat=0.10 test.qcow2 8G > > With the same release, qemu 1.7, a new qemu-img subcommand was > introduced that allows converting between both versions, so you can > downgrade your existing v3 image to the format known by RHEL 6 like > this: > > qemu-img amend -f qcow2 -o compat=0.10 test.qcow2 > > However, it looked to me as if F20 still had qemu 1.6, so you shouldn't > be seeing any of this, and your qemu-img may not have the 'amend' > subcommand. Maybe one of the package maintainers can comment on any > patches that F20 has on top of 1.6?
virt-manager in f20 uses compat=1.1 by default for new qcow2 images. Unfortunately we didn't add any UI to change that setting, so you'll have to create the qcow2 images by hand behind virt-manager's back. The other option is grab a newer qemu from fedora-virt-preview so you can use the qemu-img amend command: https://fedoraproject.org/wiki/Virtualization_Preview_Repository - Cole _______________________________________________ virt mailing list virt@lists.fedoraproject.org https://admin.fedoraproject.org/mailman/listinfo/virt
