AMD demos live migration between Intel and AMD processors

For the first time, AMD and Red Hat demonstrated that live migration of virtual machines across AMD and Intel Xeon-based servers is possible. To date, live migration has been possible only between similar processor families.

Today, Sunnyvale, Calif.-based Advanced Micro Devices Inc. (AMD) and Raleigh, N.C.-based Red Hat Inc. proved that it is possible to live-migrate virtual machines from an AMD-based server to an Intel Xeon-based one using AMD's soon-to-be released 45-nanometer quad-core processor, Shanghai.

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For the first time, AMD demonstrated live migration of a virtual machine (VM) from a dual-socket Intel Xeon dual-processor quad-core E5420-based system to a system based on the upcoming 45-nm quad-core AMD Opteron using Red Hat virtualization while doing their normal daily compute work without any interruptions.

Until now, the capability to live-migrate between different processor families was not possible and has typically been restricted to servers based on the same processor families. At the same time, one shouldn't get too excited quite yet; while AMD's Shanghai chip can live-migrate VMs to and from Intel Xeon-based servers, it isn't available to end users yet, said Tim Mueting, AMD's virtualization expert.

Until now, the capability to live-migrate between different processor families was not possible.

"This is just a technology demonstration. The ability to do a live migration between Intel and AMD is not yet a product," Mueting cautioned. "There have been statements from vendors, who I don't want to mention, saying that it isn't possible to live-migrate across different processors...But as we see with this demo, that isn't true."

Even though AMD demonstrated live migration using Red Hat virtualization, theoretically live migration between Intel and AMD systems could be applied to VMware ESX, Citrix XenServer or anything else, Mueting said.

Expected to be released this month, AMD's next-generation 45-nm quad-core processor will include all the virtualization-assist technologies of former generations, such as extended migration features that were available in AMD chips since its Rev-E processors. But the capability wasn't used until recently, Mueting said. "Extended migration is just now being used by VMware as part of its enhanced VMotion compatibility, which allows for cross-generational live migration between different AMD processors families.

AMD's hope is that the extended migration feature can be applied to Intel-based systems, and the company has worked with technology providers to make it happen. "Customers would like this capability to migrate between different vendors, and we are encouraging our partner ecosystem to come up with a solution," Mueting said.

VMware, the largest virtualization software provider in the market, does not support live migration across different types of processors because they don't consider it stable to migrate live VMs between Intel and AMD processors; while AMD and Intel quad-core processors are similar, there are differences that could affect VM reliability, according to a VMware engineer, who wished to remain annonymous.

But, "VMware currently provides full support for Enhanced VMotion Compatibility, which allows live migration of enterprise workloads across different processor families within the same CPU vendor. This technology provides customers the flexibility to move these workloads across different processor iterations in a stable and reliable way. Attempting to make cross-vendor x86 instruction sets and features compatible in a VM for live migration puts this stablity at risk and so we have not pursued it"," said Richard Brunner, Chief Platform Architect, R&D, VMware.

Playing catchup
For more than a year, AMD has pushed vendors to broaden live migration capabilities for, presumably because it would remove the barriers to including AMD-based systems in virtualization pools that are already based on Intel.

By the same token, this may be the reason Intel executives have claimed there is no real value in allowing live migration across different CPUs. In a recent interview with about interoperability and cloud computing, William Cox, director of cloud strategy at Intel, said "I'm not so worried about live migration between different processor based servers. I don't hear that it is a real issue."

But users like Bob Plankers, the lead Linux and VMware systems engineer at the University of Wisconsin, disagree and want the flexibility to live-migrate between vendor platforms. Plankers said it would also benefit users because it would remove vendor lock-in allow and give users the freedom to grow their environment with whatever CPU hardware they choose.

"[Today],when you want to grow your virtual infrastructure you have to do it with the CPU vendor you already have, regardless of price, performance, or feature considerations," Plankers said.

Because AMD was late to release its quad-core processor, Barcelona, Intel has dominated the hardware market with their Xeon quad-core CPUs. "As such, AMD basically locked themselves out of the virtualization market, because there wasn't any cross-compatibility, and everybody who built a virtual environment did so with Intel CPUs," Plankers said.

"AMD lost almost a year of time to Intel and now has to play catchup. The only way they can sell into Intel's very entrenched market is if they find a way to remove the vendor lock-in," Plankers said. "If this works, they'll be left with only an image problem, but if they continue to mind the details, produce rock-solid hardware, and keep up their trend of being a good value, their image will fix itself rapidly."

Let us know what you think about the story; email Bridget Botelho, News Writer. And check out our Server Virtualization Blog.

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