Closer Look

FedTech test drives the coming Windows Server 2008 to offer a peek at the OS’ built-in virtualization tool, Hyper-V.

Sean Gallagher, who began his career as an IT project manager for the Navy, has spent two decades as a technology writer and reviewer.

Technology managers in government and industry increasingly feel crushed between expanding needs and fixed resources.

The burden of managing and maintaining more servers — and ensuring the availability of an ever-growing number of applications — continues to grow, while data-center space, power and cooling restrictions make adding more servers problematic.

That’s why server virtualization has become such an essential tool. Server virtualization technology lets a single server take on the roles of several, running multiple operating systems and applications within compartmentalized virtual servers. But virtualization isn’t just for the data center. Virtualized servers can help in branch offices by combining multiple server roles into a single machine, keeping applications and services secure by giving administrators access only to the services for which they have privileges.

Coming to an OS Near You

Microsoft has offered a free add-on virtualization component, Microsoft Virtual Server 2005, since June 2006. Based on technology acquired from Connectix, Virtual Server runs on top of Windows Server 2003. With the latest release, the software lets Windows and Linux sessions run within Windows Server, but this is an unsupported function.

With the release of Microsoft Windows Server 2008 (expected this month), virtualization will be built right into the operating system. Administrators will be able to configure virtual sessions of nearly any OS that runs on Intel or AMD processors as a “guest” OS running on the same physical server, and manage them from within the familiar Windows Server management console.

To understand the new Hyper-V virtualization technology, FedTech obtained a preview release of Windows Server 2008 Release Candidate 0 to see how Microsoft more tightly integrated virtualization into Windows and to look at how it can ease the configuration and management of virtual servers.

Although there are significant limitations to the preview in terms of supported hardware — as there are with any beta software — this early look shows a great deal of promise. When released, Windows Server 2008 will make virtualization more accessible to smaller organizations and to IT operations with largely Windows-based administration skills.

FACT:

With Hyper-V, configuring virtual servers requires as little as 8 megabytes of RAM.

The Basics

Hyper-V is a hypervisor, a program that sits between the hardware and guest OS sessions. Because Hyper-V interacts directly with the hardware, it can take direct advantage of 64-bit processors and symmetric multiprocessing (SMP). Although Virtual Server 2005 can run on 64-bit Windows, it can only be used to run 32-bit guest operating systems, and the guest sessions can’t use SMP capabilities for applications. Hyper-V lets 64-bit and 32-bit OSes run side by side on the same server.

The preview of Hyper-V installs as a set of updates to the Windows Server release candidate; when it ships, the virtualization software will be part of the full installation. Once installed, Windows server virtualization is configured and managed through Windows Server’s Server Manager console in the same fashion as the Internet Information Server (IIS) Web server or other server “roles.”

Because the management features of Windows Virtualization Services are integrated with the rest of Windows Server’s management, you can use Active Directory to control who has access to the configuration details of each virtual server. It also means that tasks, such as making snapshots of virtual servers’ states — important to disaster recovery and continuity of operations — can be automated through management tools just like any other systems management task, without specialized knowledge required of the OS running within the virtual server. Volume shadow copy service (VSS), an automated backup feature in Windows Server 2008, can make point-in-time backups of the virtual hard drives of systems without interrupting the state of the virtual servers.

For a look at other enhancements in virtualization technology,

read "Virtual Leaps."

Simple Setup

Setting up a virtual server is incredibly straightforward in Server Manager. Once you’ve selected a server running virtualization services from the Server Manager, choosing New from the Actions menu, then selecting Virtual Machine launches a wizard that walks you through configuration of a virtual server, including its memory, networking, virtual hard-disk and OS configuration.

The function will let a user configure virtual servers up to the full memory capacity of the server or create virtual hard disks — which occupy directories within the Windows file system — of up to 2 terabytes.

While it’s difficult to compare the performance of Hyper-V to other virtualization programs before its official release, one thing is certain: Windows Server 2008 will bring server virtualization into places it’s never been before and ease concerns about the learning curve of adopting virtualization technology by wrapping it in the accessible interface already familiar to Windows administrators.

What’s a Hypervisor?

The software that manages the operation of multiple virtual machines running on a single server is called a hypervisor.

There are two types of hypervisors:

• A native hypervisor, often called a Type 1 or bare-metal hypervisor, runs directly on the server hardware.

• A hosted hypervisor, or Type 2, runs within an operating system.

Virtual Server 2005 is a hosted hypervisor. Because it runs within Windows Server 2003, other guest OSes essentially run within Windows. As a result, they can’t take advantage of many of the advanced features that the host OS can, such as 64-bit processing or multiprocessing. Other hosted hypervisors include VMware Server, VMware Workstation and VMware Fusion.

Windows Server 2008’s Hyper-V is a native hypervisor. It does not run virtual servers within the Windows Server OS, but as separate virtual machines alongside it. Because Hyper-V essentially acts directly on the hardware, the virtual operating sessions can be configured to take advantage of multiple processors, 64-bit computing and other enhanced features of hardware designed specifically for virtualization. Other native hypervisors include VMware ESX Server, Sun Microsystems Logical Domains and Citrix Xen.