Hello,
          i migrated the vm to the dsetination but when i remigrate to its original host is gives me.

[root@node0 ~]# virsh migrate try3 --live  qemu+ssh://100.100.102.106/system  --unsafe
root@100.100.102.106's password:
error: internal error hostname on destination resolved to localhost, but migration requires an FQDN.

On Fri, Mar 15, 2013 at 1:10 AM, Cole Robinson <crobinso@redhat.com> wrote:
On 03/14/2013 03:17 AM, Digvijay wrote:
> [root@node0 ~]# virsh migrate --live try1 qemu+ssh://root@100.100.102.106/system
> --unsafe
> root@100.100.102.106's password:
> error: operation failed: migration job: unexpectedly failed
> error: Reconnected to the hypervisor
>

CC-ing libvirt-users

I think that virsh command should work. Look at
/var/log/libvirt/qemu/$vmname.log on both the source host and the destination
host.

>
> I tried to run the migration but it is not doing profitably.I also used virtual
> machine manager but it is giving me " unsafe operation"
>
> Unable to migrate guest: Unsafe migration: Migration may lead to data corruption
> if disks use cache != none
>
> Traceback (most recent call last):
>   File "/usr/share/virt-manager/virtManager/asyncjob.py", line 96, in cb_wrapper
>     callback(asyncjob, *args, **kwargs)
>   File "/usr/share/virt-manager/virtManager/migrate.py", line 553, in _async_migrate
>     vm.migrate(dstconn, migrate_uri, rate, live, secure, meter=meter)
>   File "/usr/share/virt-manager/virtManager/domain.py", line 1163, in migrate
>     self._backend.migrate(destconn.vmm, flags, newname, interface, rate)
>   File "/usr/lib64/python2.7/site-packages/libvirt.py", line 822, in migrate
>     if ret is None:raise libvirtError('virDomainMigrate() failed', dom=self)
> libvirtError: Unsafe migration: Migration may lead to data corruption if disks
> use cache != none

Like the error says, your disks need to have cache=None or libvirt won't allow
the migration. You can change that setting per disk in the VM details UI in
virt-manager.

- Cole