A while back I received a note from Red Hat's PR company that exclaimed that Red Hat and AMD had successfully migrated a running virtual machine from a dual socket Intel Xeon DP Quad Core E5420-based system to a system based on the forthcoming 45nm Quad-Core AMD Opteron™ processor, utilizing Red Hat’s open source virtualization software. Neat trick.
Here's what Red Hat and AMD had to say for themselves
AMD (NYSE: AMD), in collaboration with Red Hat, today demonstrated for the first time “live migration” of a virtual machine across vendor platforms. Live migration enables the movement of running virtual machines (VMs) from one physical server to another without disrupting service to the end user, something that, till now, has only been demonstrated across systems based on one vendor’s platforms. Today’s live migration demonstration moves a live VM from an dual socket Intel Xeon DP Quad Core E5420-based system to a system based on the forthcoming 45nm Quad-Core AMD Opteron™ processor, utilizing Red Hat’s high-performance open source virtualization software. See the demonstration on the AMD Unprocessed YouTube Channel https://www.youtube.com/watch?v=EuhU6jJjpAQ
Many believe that industry standard microprocessors are identical expect for their performance ratings. Nothing could be further from the truth.
Both Intel and AMD have changed microprocessor capabilities and, to some extent, the instruction set, each time a new microprocessor is released. This means that suppliers of virtual machine software have had to develop their code for the lowest common denominator, that is the functions and instructions that can be found universally on industry standard microprocessors. The fact that some microprocessors have the capabilitiy of running both 32-bit and 64-bit code just adds to the excitement faced by virtual machine software suppliers.
So, moving a running virtual machine from a system sporting one supplier's microprocessors to another machine equiped with another supplier's microprocessor demonstrates a great deal of industrial sorcery and skill. That being said, it seems to me that others demonstrated this feat long ago. I believe that Citrix, VMware and Virtual Iron, among others, have shown similar demonstrations in the past.