In our rolling review of Windows 2008 Server components, we've saved the most intriguing--Hyper-V--for last.

Our take? Hyper-V is great for basic Windows server consolidation, and it works well in rudimentary high-availability scenarios, but it's no match for the wide range of enterprise capabilities offered by Citrix XenServer and VMware's suite of products.

First things first: As you deploy Hyper-V, you'll discover that you will need true 64-bit hardware to run it; Citrix XenServer requires a 64-bit machine as well. In contrast, VMware's ESX Server can run on standard 32-bit hardware. Customers may find that some of their most capable hardware won't run Hyper-V.

Further, if you've been running a prerelease version of Hyper-V, you'll need to make sure you bring your hypervisor up to a post-release version by installing the KB950050 update package.

One of the niceties of Hyper-V is the Microsoft Management Console snap-in that's installed along with the Hyper-V server. The Hyper-V MMC snap-in runs much faster than the bloated VirtualCenter client. And if you're running Windows Vista Service Pack 1, you can remotely manage your Hyper-V servers with the same server-based snap-in by installing the KB952627 update.

Building virtual machines in Hyper-V is very easy to do. A wizard-driven dialogue takes you though the process of allocating the memory, processing, network, and storage resources required for the new virtual machine. Once complete, you can easily mount the ISO image needed to boot and install the new VM operating system.

OS SUPPORT

Hyper-V lacks support for guest operating systems, a huge differentiator between Hyper-V and both ESX and XenServer. Hyper-V officially supports only select Microsoft server and client operating systems, as well as SUSE Linux. ESX supports practically every OS ever built, on almost any hardware, and makes Hyper-V's guest OS support look insufficient. XenServer isn't as capable as ESX with respect to guest OS support, but its support for a variety of Linux distributions makes Xen more capable than Hyper-V.

There's no direct way to clone a VM to a template for mass distribution via the Hyper-V MMC snap-in: You can clone a VM within the Hyper-V manager by running an export of a Hyper-V virtual hard disk file, then attaching the exported file during the VM creation process--a clunky procedure. VMware's VirtualCenter owns the advantage, at least until Microsoft's System Center Virtual Machine Manager 2008 arrives. It's now in beta and set for release late this year.

Rapid VM provisioning is key for organizations virtualizing their production environments: High availability and zero-downtime migration are equally important. VMware provides both capabilities now.