On 11/05/2012 01:52 PM, Joe Linoff wrote:
Hi Eric:
[please don't top-post on technical lists]
Thank you for your suggestions. Here is what happened when I tried the snapshot. I will try the dd a bit later.
VERSIONS virsh: 0.9.10 qemu: 2.0.12
Huh? The current upstream version of qemu is 1.2; I don't recognize the 2.0.12 numbering.
DOM: webdev
$ ls -l /proc/13196/fd/9 lrwx------. 1 qemu qemu 64 Nov 5 11:57 /proc/13196/fd/9 -> /tools/vm/images/webdev.img (deleted)
$ cp /proc/13196/fd/9 /tools/vm/images/webdev.img cp: cannot stat `/proc/13196/fd/9': Stale NFS file handle
$ virsh snapshot-create-as webdev \ --no-metadata \ --disk-only \ --diskspec /tools/vm/images/webdev.img,file=/tools/vm/images/webdev.img1 error: unsupported configuration: no disk named '/tools/vm/images/webdev.img'
What does this say? virsh domblklist webdev That is the name of the disk where you are creating the snapshot. The --diskspec line needs two pieces of information: a designation for the current file being snapshotted (either the absolute path you used in your xml, or the shorthand name like 'vda' - valid names are found by the domblklist command); and the name of the new file to create the snapshot as. The fact that your error message complains about "no disk named '/tools/vm/images/webdev.img'" says that you probably didn't spell the file the same as it was named in the XML; seeing the domblklist command will make it clear what name you should be using instead.
# Pull the contents into the new file virsh blockpull $dom /tmp/guest.img1 --wait --verbose
For the blockpull command, the same usage applies - you name the disk by its path (but note that you just changed the path as a result of the snapshot-create-as command; as another domblklist would prove) or by its device name, such as vda. -- Eric Blake eblake@redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org