Hi, finally I am posting something to this list :) I read it for quite some time now and I am an ovirt user since 3.0. I updated an engine installation from 3.2 to 3.6 (stepwise of course, and yes I know that's pretty outdated ;-). Then I updated the associated Centos6 hosts vdsm as well, from 3.10.x to 3.16.30. I also set my cluster comp level to 3.5(3.6 comp level is only possible with El7 hosts if I understood correctly). After my first failover test a VM could not be restarted, altough the host where it was running could correctly be fenced. The reason according to engine's log was this: VM xxxxxxxx is down with error. Exit message: internal error process exited while connecting to monitor: qemu-kvm: -device virtio-serial-pci,id=virtio-serial0,max_ports=16,bus=pci.0,addr=0x4: Duplicate ID 'virtio-serial0' for device I then recognized that I am not able to run this VM on any host. Ich checked the virtual hardware in the engine database and could confirm that ALL my VMs had this problem: 2 devices with alias='virtio-serial0' e.g.: ---- engine=# SELECT * FROM vm_device WHERE vm_device.device = 'virtio-serial' AND vm_id = 'cbfa359f-d0b8-484b-8ec0-cf9b8e4bb3ec' ORDER BY vm_id; -[ RECORD 1 ]-------------+------------------------------------------------------------- device_id | 2821d03c-ce88-4613-9095-e88eadcd3792 vm_id | cbfa359f-d0b8-484b-8ec0-cf9b8e4bb3ec type | controller device | virtio-serial address | boot_order | 0 spec_params | { } is_managed | t is_plugged | f is_readonly | f _create_date | 2016-01-14 08:30:43.797161+01 _update_date | 2016-02-10 10:04:56.228724+01 alias | virtio-serial0 custom_properties | { } snapshot_id | logical_name | is_using_scsi_reservation | f -[ RECORD 2 ]-------------+------------------------------------------------------------- device_id | 29e0805f-d836-451a-9ec3-9031baa995e6 vm_id | cbfa359f-d0b8-484b-8ec0-cf9b8e4bb3ec type | controller device | virtio-serial address | {bus=0x00, domain=0x0000, type=pci, slot=0x04, function=0x0} boot_order | 0 spec_params | { } is_managed | f is_plugged | t is_readonly | f _create_date | 2016-02-11 13:47:02.69992+01 _update_date | alias | virtio-serial0 custom_properties | snapshot_id | logical_name | is_using_scsi_reservation | f ---- My solution was this: DELETE FROM vm_device WHERE vm_id='cbfa359f-d0b8-484b-8ec0-cf9b8e4bb3ec' AND vm_device.device = 'virtio-serial' AND address = ''; (just renaming one of the aliases to virtio-serial1" did not help) Is this a known issue? Couldn't find anything so far. Should I also post this to the developer list? I am not subscribed there yet, wanted to check out here first. thanks in advance and all the best Jojo @ LINBIT VIE