Opinion: RTM edition of Microsoft Hyper-V adds speed

June 27, 2008 (Computerworld) Yesterday afternoon, Microsoft released its virtualization product, Hyper-V, to manufacturing. Previously, the company had promised to make a production-supported version of Hyper-V available to Windows Server 2008 customers within 180 days of the official release of the operating system itself. By releasing Hyper-V in late June, Microsoft beat its self-imposed deadline by about a month, although delivering less than was originally promised.

There have been public release candidates available since early this year. In this piece, I'll take a look specifically at the release-to-manufacturing, or RTM, edition, noting improvements and changes.

Performance differences

The most notable -- and the most significant -- change between the initial release candidate version (RC0) of Hyper-V and the RTM edition is better performance. Most of the performance work was done between RC0 and RC1, but not many people knew about it due to (a) not-so-wide a release and (b) a ban on performance testing by Microsoft. The company just wasn't ready for it to be tested on a wide scale. The performance story between RC1 and RTM is identical.

QLogic, a vendor of storage-area networks (SAN) and other components, tested Hyper-V RC1 on one of its own host bus adapters (HBA), based on Fibre Channel. QLogic hooked the HBA up to a storage array, to test the number of I/O operations per second supported by a virtual machine (VM) as opposed to real, physical hardware. The results were impressive, and are equally so under RTM, as the underlying performance plumbing didn't change.

In particular, a setup based on intensive I/O applications -- one that is common to mail server and database server configurations -- showed that 120,426 I/O operations per second were possible with real hardware, compared with 116,720 per second on a Hyper-V-based VM. In other words, the VM was able to saturate the hardware enough to achieve 97% of the storage performance of a physical server.

Similar tests were performed by QLogic in a variety of configurations, each mimicking a specific type of storage operation, and results were similar -- as low as 88% of real hardware in one scenario and as high as 99.93% in another. (These results are here.)

Indeed, performance has been good enough that Microsoft claims it has been running its popular msdn.microsoft.com and technet.microsoft.com sites from Hyper-V RC1 VMs for months now. These sites combined receive around 4 million hits per day. Each IIS7 VM runs four virtual CPUs with 10GB of RAM, and the physical hosts have two quad-core CPUs with 32GB of RAM and host three VMs. Microsoft will be migrating to the RTM version of Hyper-V on these production machines very soon, as part of its major push to virtualize up to 25% of its internal IT infrastructure this year.