Online migration failure - no useful info?

I have a running ubuntu 12.04 guest on proxmox2. I am trying to migrate it to proxmox1. It has no local resources or anything. I fire up the migrate (same results from cli as gui) and see this:

root@proxmox2:/var/log# qm migrate 100 proxmox1 --online
Apr 04 09:49:12 starting migration of VM 100 to node 'proxmox1' (10.0.0.8)
Apr 04 09:49:12 copying disk images
Apr 04 09:49:12 starting VM 100 on remote node 'proxmox1'
Apr 04 09:49:13 starting migration tunnel
Apr 04 09:49:13 starting online/live migration on port 60000
Apr 04 09:49:13 migrate_set_speed: 8589934592
Apr 04 09:49:13 migrate_set_downtime: 0.1
Apr 04 09:49:15 ERROR: online migrate failure - aborting
Apr 04 09:49:15 aborting phase 2 - cleanup resources
Apr 04 09:49:15 migrate_cancel
Apr 04 09:49:16 ERROR: migration finished with problems (duration 00:00:04)
migration problems

Any ideas where I should start looking for info? /var/log/syslog and /var/log/daemon have nothing helpful :(

p.s. I can migrate other guests just fine...