Microsoft last week shipped a public release candidate version of its upcoming Windows Server 2008 product, and this version came with a little surprise: the first public beta version of the company's Hyper-V virtualization technologies (previously code-named Viridian). Although Windows 2008 is, by and large, an amazing update with numerous advances, Hyper-V remains a big question. The problem is that while Microsoft has been engineering a way to elegantly host virtualized OSs on top of its Windows Server core, the competition and the marketplace haven't stood still. Today, enterprise customers expect a proven level of maturity and stability from their virtualization platform, which is completely understandable. After all, this is a platform on which they run mission-critical solutions. Virtualization has moved far beyond its original development, testing, and consolidation uses. But Hyper-V remains a wild card. The first version of the system will provide a hypervisor-based virtualization platform that relies, naturally enough, on Windows Server. It's 64-bit only, and will thus run only on the x64 versions of Windows 2008, in a full install or via Server Core. It supports quick migration cluster-based high-availability features (new to the beta), but not true no-downtime failover. From a management perspective, Hyper-V is pretty bare-bones: Microsoft includes a management console for managing a single machine, but you'll want to purchase and install System Center Virtual Machine Manager (VMM), which will be updated next year with Hyper-V support, to manage a virtualized data center. Although Microsoft's entry into this market is notable, it's hard not to overstate how far behind the company is in delivering this kind of solution. Microsoft has been shipping host-based virtualization solutions like Virtual PC and Virtual Server for years, but the largest player in this market, VMware, first shipped a hypervisor-based virtualization solution years ago. And that solution, VMware Infrastructure's ESX Server, has evolved dramatically over the years to include exactly the kinds of functionality that customers demand and expect. By way of comparison, the Microsoft offering appears to compete most closely with VMware's entry-level VMware Infrastructure Foundation product. There are, of course, core architectural differences between the products. Although VMware is in the midst of shipping a true bare metal virtualization solution, ESX Server 3i, which has the support of all the major enterprise server vendors, Microsoft's Hyper-V leverages the Windows driver model for compatibility reasons. VMware's solution, thus, arguably offers a smaller attack surface. Microsoft's solution might eventually have better hardware support. Again, it's a wild card. It's hard to prophesize how the market is going to respond to Microsoft first and currently immature offering. My guess is that the software giant will attract a significant chunk of the virtualization market solely by releasing Hyper-V and that it will slowly evolve the platform in a bid to catch up with VMware's more mature and capable offerings. As VMware Senior Director Reza Malekzadeh told me during a recent conversation, many had predicted that VMware would founder when Microsoft purchased Connectix's virtualization technologies several years ago, but the company has only grown and flourished since. It's quite possible that it will weather this storm ably as well. I hope that's what happens. One aspect of VMware's strategy that I've always appreciated is what appears to be a very real concern for the needs of customers. In the end, the best technology should be rewarded. In the virtualization market, that technology is currently coming from VMware, not Microsoft. If you're interested in testing Hyper-V, which I do recommend, you can download the x64 version of Windows Server 2008 Enterprise release candidate 1 (RC1). Hyper-V is available as an optional role install within that release. http://www.microsoft.com/windowsserver2008/audsel.mspx