Nova live migration fails - InvalidCPUInfo: Unacceptable CPU info: CPU doesn't have compatibility.

Having issues getting live migrations to functions between two compute nodes. One is an Opteron G4 and the other is an Opteron G5. I can migrate from the G4 to the G5 just fine. When I try to migrate an instance from the G5 node to the G4 node I get an error message: InvalidCPUInfo: Unacceptable CPU info: CPU doesn't have compatibility. This is despite having the following setting in my /etc/nova/nova.conf on the G5 machine. [libvirt] cpu_mode = custom cpu_model = Opteron_G4 Is this not the setting I'm looking for? What can I do to make this work? Torin Woltjer Grand Dial Communications - A ZK Tech Inc. Company 616.776.1066 ext. 2006 www.granddial.com