[ovirt-users] Strange migration issue

Dear All, I've using ovirt from 3.4 and we have a strange, rarely problem with live migrations. - In most of case impossible to do a live migrate of VMs that have a lot of memory (16 gigs and more up to 40 GB) . - Those are need to try and try until the migration will be successful - impossible to understand why does working in a case and doesn't in another - it is happening always if there bigger load on vms, but only on big memory VM-s - The small VMs (2-4-8 gigs) can migrate without problems - In very rarely cases possible to migrate on first try. - We using the memory ballooning function on all of VMs. We using dedicated migration network with separated vlans, but on same physical lan (1gbe) with ovirtmgmt. At this moment, we don't use QoS for dedicate bandwidth. What can I do ? Thanks in advance, Regards, Tibor