[libvirt] Using Restore in another host.

[Michal Novotny]

Hi Marcela,
is any other guest on the host that cannot restore this VM working fine ?

You could also try running the:

*/# LIBVIRT_DEBUG=1 virsh restore sv-chubut-2011-04-04-17:38 2>
virsh-restore.log

/*command which would enable the libvirt logging and output the debug
log into the virsh-restore.log file. This file could be sent to the list
for analysis what's wrong.

Thanks,
Michal

On 04/05/2011 11:57 AM, Marcela Castro León wrote:
> Hello Daniel
> Thank you for all your information, but I still didn't solve the
> problem. I tried the option you mention, with two differents guest
> into two differents host, but all the cases I've got:
>
> */virsh # restore sv-chubut-2011-04-04-17:38/*
> */error: Failed to restore domain from sv-chubut-2011-04-04-17:38/*
> */error: monitor socket did not show up.: Connection refused/*
>
> I cannot get any useful information (at least form me) on the log you
> mention.
> I'd appreciate a lot a new suggestion.
> Thanks
> Marcela
>
>
>
>
> 2011/4/4 Daniel P. Berrange <berrange at redhat.com
> <mailto:berrange at redhat.com>>
>
>     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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-- 
Michal Novotny <minovotn at redhat.com>, RHCE
Virtualization Team (xen userspace), Red Hat