Microsoft's Windows Server 2008 introduced Hyper-V, the hypervisor-based virtualization feature that enables computers running the server operating system to play host to guest virtual machines.

But organizations that have not yet implemented Windows Server 2008 can begin to benefit from the new hypervisor thanks to Microsoft Hyper-V Server 2008. Launched in October, this is a free, standalone hypervisor-based server virtualization product that allows customers to build and run virtual machines on a single physical host server.

There are a number of ways organizations can benefit from Hyper-V Server 2008, such as in a corporate test and development environment. Technicians can use Hyper-V Server 2008 to set up and test a wide variety of operating scenarios in a secure and stable virtual environment using virtual machines or test new application builds on different operating systems with a variety of virtual hardware configurations.

Since the product has been designed to work with Microsoft's Virtual Machine Manager, part of the System Center family of management products, testers can take prebuilt virtual machines from a corporate virtual machine library to run on Hyper-V Server 2008. This is a much more efficient way of carrying out testing than building virtual machines from scratch for each test (and deleting them afterwards to avoid "virtual machine sprawl") or waiting for physical machines to be made available.

But Hyper-V Server 2008 is not just designed for test and development environments. It is also an ideal solution for smaller organizations or remote sites of larger organizations that could benefit from consolidating several physical servers onto a single machine.

In remote offices in particular, where there is often little or no on-site IT support, Hyper-V Server 2008 provides a way to virtualize e-mail, file and print, application, and other servers onto a single physical computer that can then be managed remotely. This has several advantages, including reducing maintenance and management costs, reducing power consumption, using up less physical space, and leaving only a single server to back up. Backup is made easier because Hyper-V Server 2008 has integrated Volume Shadow Services (VSS) and Live Backup support.

Hyper-V Server 2008 has been designed to have as small a footprint as possible. It has been stripped down to include only the core operating system components needed to run what is roughly the equivalent of Windows Server 2008's Server Core installation with the Hyper-V role, with which it shares the same driver model and update mechanism. It has been further streamlined by the removal of a few of the higher-end features of the Hyper-V included in Windows Server 2008. These features, which are only likely to be of use in large enterprise deployments, include Quick Migration - which moves a paused virtual machine from one physical host to another - and clustering.

Thanks to this "thin" design, Hyper-V Server 2008 does not require particularly powerful hardware to run on, and organizations can benefit from this by virtualizing legacy operating systems such as Windows Server 2003 and Windows Server 2000, Linux operating systems, or even workloads that have been virtualized using Microsoft Virtual Server, on older, repurposed hardware.

The base requirement is an x64 processor with Intel VT or AMD Virtualization hardware-assisted virtualization capabilities, and the software supports up to four processors with up to four cores each. In theory it can host up to 192 virtual machine guests running 64 bit or 32 bit versions of:

• Windows Server 2008, 2003 or 2000
• SUSE Linux Enterprise Server 10
• Windows Vista
• Windows XP

Installing Hyper-V Server 2008 on a new machine is a similar experience to installing Windows Server 2008, but once the installer program has completed users are in for a shock: like a Server Core installation, Hyper-V Server 2008 has essentially no graphical user interface at all: instead users are presented with a simple text-based Hyper-V Configuration window with 13 numbered options. These can be selected to join the server to a workgroup or domain, configure Windows Update, change the server name, enable Remote Desktop, configure TCP/IP settings, and change the date and time and various regional and language options. As with Server Core, a few elements of the configuration process (such as the "Data and Time" and "Regional and Language Options" applets) have their own GUI, but overall the interface is minimalist in the extreme.

This begs an important question: how do users create, configure, and manage virtual machines? The answer is that they don't. At least, not on Hyper-V Server 2008 itself -- all of these tasks are carried out remotely in one of the following ways:

• Smaller organizations that have not yet deployed Windows Server 2008 can download and run the Hyper-V Manager MMC on Windows Vista SP1 machines to manage Windows Server 2008 remotely. This provides a powerful graphical user interface for carrying out management tasks such as creating or importing new virtual machines, creating snapshots, rebooting machines, and monitoring what machines are running on the Hyper-V Server 2008 at any given time.
• Larger organizations that have already implemented Windows Server 2008 can manage Hyper-V Server 2008 using the Hyper-V Manager Microsoft management console (MMC), which is included in the product.
• The most sophisticated option for larger organizations running Microsoft System Center is to manage Windows Server 2008 machines remotely using System Center Virtual Machine Manager. This can also be used to manager other virtual machines running on Windows Server 2008 installations elsewhere in the organization.
• Hyper-V Server 2008 also includes a Windows Management Instrumentation (WMI) interface for remote management software

  Hyper-V Server 2008 is certainly not intended to be used to build a fully virtualized IT infrastructure - for that organizations should used the Hyper-V virtualization feature of Windows Server 2008. But for small organisations, branch office server consolidation and test and development environments; there is no doubt that it is a very powerful and cost-effective solution.