Windows Server 2008 R2 Hyper-V
Beginning with Windows Server 2008, server virtualization using Hyper-V technology has been an integral part of the operating system. Windows Server 2008 R2 introduces a new version of Hyper-V.
Hyper-V in Windows Server 2008 R2 includes five core areas of improvement for creating dynamic virtual data centers:
- Increased availability for virtualized data centers
- Improved management of virtualized data centers
- Increased Performance and Hardware Support for Hyper-V Virtual Machines
- Improved Virtual Networking Performance
- A simplified method for physical and virtual computer deployments by using .vhd files
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 much-anticipated 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.
- Cluster Shared Volumes (CSV)
With Windows Server 2008 R2, Hyper-V uses Cluster Shared Volumes (CSV) storage to simplify and enhance shared storage usage. CSV enables multiple Windows Servers to access SAN storage using a single consistent namespace for all volumes on all hosts. Multiple hosts can access the same Logical Unit Number (LUN) on SAN storage. CSV enables faster live migration and easier storage management for Hyper-V when used in a cluster configuration. Cluster Shared Volumes are available as part of the Windows Failover Clustering feature of Windows Server 2008 R2.
- Improved Cluster Node Connectivity Fault Tolerance
Because of the architecture of CSV, there is improved cluster node connectivity fault tolerance that directly affects virtual machines (VMs) running on the cluster. The CSV architecture implements a mechanism, known as dynamic I/O redirection, where I/O can be rerouted within the failover cluster based on connection availability.
- Enhanced Cluster Validation Tool
Windows Server 2008 R2 includes a Best Practices Analyzer (BPA) for all major server roles, including Failover Clustering. This analyzer examines the best practices configuration settings for a cluster and cluster nodes.
- Dynamic VM storage
Windows Server 2008 R2 Hyper-V supports hot plug-in and hot removal of storage. By supporting the addition or removal of Virtual Hard Drive (VHD) files and pass-through disks while a VM is running, Windows Server 2008 R2 Hyper-V makes it possible to reconfigure VMs quickly to meet changing workload requirements. This feature allows the addition and removal of both VHD files and pass-through disks to existing SCSI controllers for VMs.
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
- Hyper-V in Windows Server 2008 R2 now supports up to 64 logical processors in the host processor pool. This is a significant upgrade from previous versions and allows not only greater VM density per host, but also gives IT administrators more flexibility in assigning CPU resources to VMs.
- Also new, Hyper-V processor compatibility mode for Live Migration allows Live Migration across different CPU versions within the same processor family, (e.g.”Intel Core 2-to-Intel Pentium 4” or “AMD Opteron-to-AMD Athlon”) enabling migration across a broader range of server host hardware.
- The new Hyper-V also adds performance enhancements that increase virtual machine performance and power consumption. Hyper-V now supports Second Level Address Translation (SLAT), which uses new features on today’s CPUs to improve VM performance while reducing processing load on the Windows Hypervisor and new Hyper-V VMs will also consume less power by virtue of the new Core Parking feature implemented into Windows Server 2008 R2.
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 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 6 times larger payloads per packet, which improves not only overall throughput but also reduces CPU utilization for large file transfers.
Simplified Method for Physical and Virtual Computer Deployments
Historically, different methods have been used to deploy operating systems and applications to physical and virtual computers. For virtual computers, the .vhd file format has become a de facto standard for deploying and interchanging preconfigured operating systems and applications. Hyper-V in Windows Server 2008 R2 supports two important updates concerning .vhd files.
First, administrators can now add and remove vhd files, as well as pass-through disks attached to a virtual SCSI controller on a running VM, without requiring a reboot. This offers more flexibility when it comes to handling storage growth needs without requiring additional downtime. It also provides more flexibility in data center backup scenarios as well as new scenarios in complex Exchange and SQL Server deployments.
Windows Server 2008 R2 also supports the ability to boot a computer from a .vhd file stored on a local hard disk. This allows you to use preconfigured .vhd files for deploying virtual and physical computers. This helps reduce the number of images you need to manage and provides an easier method for test deployment prior to deployment in your production environment.