Re: [libvirt] Using Restore in another host.
On Sun, Apr 03, 2011 at 10:43:45AM +0200, Marcela Castro León wrote:
Hello:
I need to know if I can use the restore operation (virsh o the equivalent in
libvirt) to recover a previous state of a guest, but recovered previously in
another host.
I did a test, but I got an error:
The exactly sequence using virsh I testes is:
On [HOST SOURCE]: Using virsh
1) save [domain] [file]
2) restore file
3) destroy [domain]
On [HOST SOURCE] using ubuntu sh
4) cp [guest.img] [guest.xml] [file] to HOST2
On [HOST TARGET] using virsh
5) define [guest.xml] (using image on destination in HOST2)
6) restore [file]
As a general rule you should only ever 'restore' from a
file *once*. This is because after the first restore
operation, the guest may have made writes to its disk.
Restoring a second time the guest OS will likely have
an inconsistent view of the disk & will cause filesystem
corruption.
If you want to be able to restore from a saved image
multiple times, you need to also take a snapshot of
the disk image at the same time, and restore that
snapshot when restoring the memory image.
That aside, saving on one host & restoring on a
different host is fine. So if you leave out steps
2+3 in your example above, then your data would
still be safe.
The restore troughs the following message:
*virsh # restore sv-chubut-2011-04-01-09:58
error: Failed to restore domain from sv-chubut-2011-04-01-09:58
error: monitor socket did not show up.: Connection refused*
There is probably some configuration difference on your 2nd host
that prevented the VM from starting up. If you're lucky the file
/var/log/libvirt/qemu/$NAME.log will tell you more
Daniel
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