Nope, never. If a vm needs permanently moving from one core to another (which would be unusual for us), we just spin it down and dd the lvm volumes for that gue

Nope, never. If a vm needs permanently moving from one core to another (which would be unusual for us), we just spin it down and dd the lvm volumes for that guest via ssh and then change the mac. It helps that we don't filter on mac. The main reason for tieing the addresses to the underlying core is to avoid accidentally allocating the same mac to two different vms (since at the moment vm creation is still a relatively manual process for us - hoping to improve this in the future though!).