Thanks for your answer

2013/5/7 Eric Blake <eblake@redhat.com>
On 05/07/2013 05:08 AM, Daniele wrote:
> Hi, I am trying to run some test and analysis while performing a wide live
> migration of a VM between two different network location. I use libvirt and
> qemu-kvm as hypervisor on Linux.
>
> The live wide migration from A to B completes successfully, instead I can't
> achieve the reverse path, from B to A (and that is right what I am
> interested to). To perform the migration I run this command in virsh: *"migrate
> --live --verbose uno qemu+ssh://root@ip.address/system"*

What version of libvirtd are you running on both the source and
destination?  There is a known nasty bug in a few versions prior to
1.0.5 where migration could trigger a race that would kill the source
libvirtd, so if you aren't testing with the latest version on both ends,
then upgrade first.  Also, what version of qemu are you running on the
two ends?

In the source host there is libvirtd 0.9.12, while in the destination host there is a modified version of the 0.9.8 (that I can't change). 
Now that you mention it, sometimes after the migration failure the libvirt daemon crashed in the destination host, not in the source host.

About the qemu version, the source host has qemu-kvm-1.1.2+dfsg-6, while the destination host has qemu-kvm-1.0.



> *
> *
> Even if dramatically slow (i guess due to some network bottleneck) the
> migration starts correctly, but it gets stuck at 96% and after some minute
> it returns this error: *"Migration: [ 96 %]error: operation failed:
> migration job: unexpectedly failed" *without further details.
>
> The libvirtd.log file in the source host says:
> *2013-05-07 11:01:18.739+0000: 9538: error :
> qemuMigrationUpdateJobStatus:945 : operation failed: migration job:
> unexpectedly failed*

Does the /var/log/libvirt/qemu/uno.log file on either the source or
destination shed more light?

Nothing interesting in the source uno.log, but I wasn't checking in the destination host log. These are its last lines:
savevm: unsupported version 3 for 'i8254' v2
load of migration failed
2013-05-07 16:27:59.682+0000: shutting down

I'm also checking the libvirtd.log in the destination host (that i didn't look before) and it seems interesting. It reports this error:
2013-05-07 16:27:59.682+0000: 16651: error : qemuMonitorIO:560 : internal error End of file from monitor
Caught Segmentation violation dumping internal log buffer:

..and following there is a really long log of the debugger with a time stamp of the last 13 seconds of the migration. You can see the whole log here: http://db.tt/LcXEvGjF



Thanks again
Daniele

 

> *
> *
> Apparently i can't find any clue of what is causing the error, do you have
> any idea/solution?
> *
> *
> (I'm not sure if this is the appropriate mailing-list, maybe it was better
> the devs list?)

This list is fine.

--
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org