Windows Server 2008 now includes Hyper-V, Microsoft's new technology for hardware virtualization. Hardware virtualization makes it possible for multiple, different OSs to run simultaneously on a computer, each in its own virtual machine that emulates a complete computer in software. The technology enables organizations to reduce the number of physical servers in their computing infrastructures and increase the operational efficiency of existing servers by breaking the bonds between workloads and physical servers. For Microsoft, hardware virtualization offers an opportunity to move customers to the new Windows Server 2008, and Microsoft partners can assist customers in planning and migration of existing computing workloads and applications to a virtualized environment and with ongoing management of the VMs. However, hardware virtualization introduces significant new hardware requirements and new management, support, and licensing challenges.

This report outlines the hardware virtualization software that Microsoft offers, looks at the tools Microsoft provides for managing virtualized servers, and examines the licensing and support implications of deploying hardware virtualization.

Introduction

Windows Server 2008 now includes Hyper-V, Microsoft's new technology for hardware virtualization. Hardware virtualization makes it possible for multiple, different OSs to run simultaneously on a computer, each in its own virtual machine (VM) that emulates a complete computer in software. The technology enables organizations to reduce the number of servers in their computing infrastructures and increase the operational efficiency of existing servers by breaking the bonds between workloads and servers. For Microsoft, hardware virtualization offers an opportunity to move customers to the new Windows Server 2008 and the newest versions of its server software, such as SQL Server and Exchange, and Microsoft partners can assist customers in planning and migration of existing computing workloads and applications to a virtualized environment and with ongoing management of the VMs. However, hardware virtualization introduces significant new hardware requirements and new management, support, and licensing challenges.

Hardware Virtualization and Hypervisors

In hardware virtualization, each OS runs in its own VM, and each machine appears to have sole access to the hardware. In reality, the hardware, including the processor, memory, graphics card, network interface, and storage devices (such as disk and CD-ROM drives), are emulated in software and all of the OSs in VMs are sharing the hardware resources of the physical server. Each VM is stored as a standard file, which Microsoft calls a Virtual Hard Disk (VHD) file, on the local computer, a network file server, or on removable storage, such as a DVD.

Hyper-V is a hypervisor, a thin layer of specialized OS software optimized for creating VMs, managing memory, and processor scheduling for the OSs installed in the VMs, and for managing communication between VMs and physical hardware. Hypervisors such as Hyper-V, Citrix's XenServer, and VMware's ESX are becoming the dominant form of hardware virtualization used to support production servers because they offer improved performance and increased reliability over so-called VM monitor products (such as Microsoft's own Virtual Server) that require a full server OS installed on the hardware. VM monitors remain useful in some situations; notably, Microsoft's Virtual Server is the only hardware virtualization technology the company offers for 32-bit systems.

Server Hardware Virtualization: Something for Everyone

Hardware virtualization has taken off first on servers because it offers the potential to increase both hardware utilization and operational flexibility. The technology has become important to IT departments, Microsoft, and its partners.

IT departments. Hardware virtualization enables an IT department to place multiple complete OS configurations with their applications on a single physical server, which can improve hardware utilization and cut down the total number of physical servers the organization must manage, reducing overall costs. In addition, hardware virtualization decouples applications from the underlying hardware, and management tools enable organizations to move VMs among servers much more easily than nonvirtualized applications. As a result, organizations can more easily balance workloads, perform maintenance, and recover from hardware or system failures, reducing overall system downtime.

Microsoft. Hardware virtualization reduces hardware costs and expenditures—leaving more money for software purchases—and drives upgrades to Microsoft's latest server editions. As Microsoft struggles with the perception that its older products, such as Windows Server 2003, are "good enough," hardware virtualization has become one of the most compelling scenarios for upgrading from legacy versions. Finally, by including the Hyper-V hardware virtualization technology in Windows Server 2008, Microsoft can protect that OS's key role by stopping customers from deploying competitive hardware virtualization products that do not depend on Windows Server.

Partners. Hardware virtualization can drive consulting engagements for partners to assist organizations in determining their current processing environment and workloads, assessing how hardware and workloads can and cannot be amalgamated, and identifying the best way to deploy hardware virtualization. In addition, partners can help customers with their new virtualization-based infrastructure, including the maintenance of both online and offline VMs. Hardware manufacturers will also benefit: hypervisors such as Hyper-V require the latest 64-bit processors and server consolidation, in general, creates a demand for larger, more powerful servers and storage hardware.

Management, Licensing, Support Challenges

Although server consolidation promises cost savings and reduced downtime, hardware virtualization introduces its own problems.

In particular, organizations that adopt hardware virtualization will need to update their systems management procedures and infrastructure to deal with VMs, and change hardware and software purchasing policies to ensure they get tested, supported system configurations. (For an overview, see the sidebar "Partners' Role in Hardware Virtualization".) Microsoft has addressed one piece of the systems management puzzle with an update to its Virtual Machine Manager product that enables management of VMs, but management technology does not completely remove the need for updated policies and procedures that ensure all of an organization's applications run as needed.

Furthermore, organizations will need to deal with new complexities in licensing and support. Because software running in VMs may routinely move from server to server, many software vendors, including Microsoft, have had to update their licensing policies, and organizations might have to upgrade licenses to take advantage of the new policies. Furthermore, many hardware and software vendors limit product support when their products are used in connection with hardware virtualization. Although Microsoft has recently liberalized support policies for its server applications, organizations will need to verify that the virtualized systems they design will be supported by Microsoft as well as the other vendors involved.

What's Ahead

This report is designed for IT managers who want to understand how hardware virtualization and Hyper-V provide a platform for server consolidation and ongoing production workloads.