Key Features of Hyper-V

Hyper-V as a part of Windows Server 2008 R2 (Standard, Enterprise, and Datacenter) adds new features to the first version of Hyper-V. For example, by using live migration in Windows Server 2008 R2 Hyper-V, you can migrate running virtual machines (VMs) from one physical computer to another and add or remove storage from a VM while it is running. In addition, Windows Server 2008 R2 Hyper-V takes better advantage of physical computer hardware with greater processor support and deeper support for physical computer hardware.

Hyper-V in Windows Server 2008 R2 includes five core areas of improvement for creating dynamic virtual data centers:

Increased Availability for Virtual Data Centers

One of the most important aspects of any data center is providing the highest possible availability for systems and applications. Virtual data centers are no exception to the need for consolidation, high availability, and, most of all, sophisticated management tools.

Hyper-V in Windows Server 2008 R2 includes the live migration feature, which allows you to move a virtual machine between two virtualization host servers without any interruption of service. The users connected to the virtual machine being moved might notice only a slight slowing in performance for a few moments. Otherwise, they will be unaware that the virtual machine was moved from one physical computer to another.

Improved Management of Virtual Data Centers

Even with all the efficiency gained from virtualization, virtual machines still need to be managed. The number of virtual machines tends to proliferate much faster than physical computers because machines typically do not require a hardware acquisition. Therefore, management of virtual data centers is even more imperative than ever before.

Windows Server 2008 R2 includes the following improvements that will help you manage your virtual data center:

• Reduced effort for performing day-to-day Hyper-V administrative tasks by using the Hyper-V Management Console.

• Enhanced command-line interface and automated management of Hyper-V administrative tasks by using PowerShell cmdlets.

• Improved management of multiple Hyper-V servers in a virtual data center environment by using System Center Virtual Machine Manager 2008.

Increased Performance and Hardware Support for Hyper-V Virtual Machines

Improved Virtual Networking Performance

The new Hyper-V leverages several new networking technologies contained in Windows Server 2008 R2 to improve overall VM networking performance. Two key examples are the new VM Chimney (also called TCP Offload) and the use of Jumbo Frames.

VM Chimney allows a VM to dump its network processing load onto the network interface card (NIC) of the host computer. This works the same as in a physical TCP Offload scenario, Hyper-V now simply extends this functionality into the virtual world. This benefits both CPU and overall network throughput performance, and it’s fully supported by Live Migration.

VM Chimney is disabled by default in Windows Server 2008 R2, primarily for short-term hardware compatibility reasons. But combined with compatible hardware, currently including vendors like Intel, VM Chimney significantly reduces the host server’s CPU burden when dealing with VM network traffic. This translates into better host system performance and a simultaneous boost to VM network throughput.

Like TCP Offloading, support for Jumbo Frames was also introduced with Windows Server 2008. Hyper-V in Windows Server 2008 R2 simply extends this capability to VMs. So just like in physical network scenarios, Jumbo Frames add the same basic performance enhancements to virtual networking. That includes up to six times larger payloads per packet, which improves not only overall throughput but also reduces CPU utilization for large file transfers.