Windows Server 2008 Revealed: Hyper-V virtualization

Computerworld - Companies of all sizes are looking to virtualization as a seemingly game-changing scenario. Server consolidation, energy efficiency, increased capacity, and simpler management and deployment are all tangible benefits to be gained from a move to virtual servers and virtually hosted services.

Microsoft Corp. has seen the light and is here to help with Hyper-V (previously known by its code name, Viridian, or by the previous brand name, Windows Server Virtualization), which was released in beta earlier this month, ahead of the planned February 2008 date.

According to the company, Hyper-V "is a next-generation hypervisor-based virtualization platform integrated with the operating system that allows you to dynamically add physical and virtual resources."

You might know about virtualization in general, but you might not be familiar with what the buzz is about. Here's a look at how Hyper-V works, its major benefits and when you can expect to deploy this feature in production environments.

How it works

To understand Hyper-V, consider its three main components: the hypervisor, the virtualization stack and the new virtualized I/O model. The Windows hypervisor basically acts to create the different "partitions" that each virtualized instance of code will run within. The virtualization stack and the I/O components provide interactivity with Windows itself and with the various partitions that are created.

All three of these components work in tandem. Using servers with processors equipped with Intel VT- or AMD-V-enabled technology, Hyper-V interacts with the hypervisor, which is a very small layer of software that is present directly on the processor. This software hooks into threads on the processor that the host operating system can use to efficiently manage multiple virtual machines, and multiple virtual operating systems, running on a single physical processor.

Since there are no third-party software products or drivers to install, you get nearly guaranteed compatibility. Along with efficient process management, you can hot-add resources to the machine hosting your virtualized services. From processors to memory to network cards to additional storage media, you can add these devices to the machine without needing to bring down any services and interrupt user sessions. You can also host 64-bit guest sessions, which is a big boon to organizations moving toward adoption of 64-bit software. You can virtualize your migration, save money on deployment costs and then assess how many physical machines you'll need when you finish your migration.

High availability

Part of the idea behind virtualization is not only to eliminate machine duplication and save on costs, but to also ensure that services are available more than they otherwise would be on unvirtualized servers. In that context, Hyper-V includes support for clustering across multiple guests. Additionally, you can cluster multiple physical machines running the Hyper-V component, so that virtualized instances can fail-over to another host should something occur with the primary host. Finally, you can migrate virtualized guests from one physical host to another with no downtime, easing servicing, planning and reorganization while significantly limiting detrimental effects on production services.