TOPIC:

Hi Salvatore.

You're right, I have an secondary NFS storage repository, but nothing inside.
I attach some screenshots where we can see that the storage of the problematic VM is on the iSCSI SR.
Maybe the problem is something related with bad communication between iscsi/drbd daemons.

Yesterday I created a small new Debian 8 machine (8Gb hard disk + 256MB memory) @ xenserver1. Once created, Migration to xenserver2 worked perfect.
And also I created a new machine with the same specifications @xenserver2, and the live migration to xenserver1 worked perfect too.

I have not tried to migrate any of the other existing VMs. Maybe that VM (losvpxe) is the only one affected with the problem.

Thanks.

I've decided to remove losvpxe and import my backup.
It looks now it works and I can move this VM between my xenservers.
It's not a nice way to "fix" the problem, but It worked.