Virtualization with Hyper-V: Overview

Businesses are under pressure to ease management and reduce costs while retaining and enhancing competitive advantages, such as flexibility, reliability, scalability, and security. The fundamental use of virtualization to help consolidate many servers on a single system while maintaining isolation helps address these demands. One of the main benefits of server consolidation is a lower total cost of ownership (TCO), not just from lowering hardware requirements but also from lower power, cooling, and management costs.

Businesses also benefit from server virtualization through infrastructure optimization, both from an asset utilization standpoint as well as the ability to balance workloads across different resources. Improved flexibility of the overall environment and the ability to freely integrate 32-bit and 64-bit workloads in the same environment is another benefit.

Business continuity is the ability to minimize both scheduled and unscheduled downtime. That includes time lost to routine functions, such as maintenance and backup, as well as unanticipated outages. Hyper-V includes powerful business continuity features, such as live backup and quick migration, enabling businesses to meet stringent uptime and response metrics.

Disaster recovery is a key component of business continuity. Natural disasters, malicious attacks, and even simple configuration problems like software conflicts can cripple services and applications until administrators resolve the problems and restore any backed up data. Leveraging the clustering capabilities of Windows Server 2008, Hyper-V now provides support for disaster recovery (DR) within IT environments and across data centers, using geographically dispersed clustering capabilities. Rapid and reliable disaster and business recovery helps ensure minimal data loss and powerful remote management capabilities.

Testing and development are frequently the first business functions to take advantage of virtualization technology. Using virtual machines, development staffs can create and test a wide variety of scenarios in a safe, self-contained environment that accurately approximates the operation of physical servers and clients. Hyper-V maximizes utilization of test hardware which can help reduce costs, improve life cycle management, and improve test coverage. With extensive guest OS support and checkpoint features, Hyper-V provides a great platform for your test and development environments.

Hyper-V, together with your existing system management solutions, such as Microsoft System Center, can help you realize the dynamic data center vision of providing self-managing dynamic systems and operational agility. With features like automated virtual machine reconfiguration, flexible resource control, and quick migration, you can create a dynamic IT environment that uses virtualization to not only respond to problems, but also to anticipate increased demands.

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. Hyper-V live migration is integrated with Windows Server 2008 R2 Hyper-V and Microsoft Hyper-V Server 2008 R2. With it you can move running VMs from one Hyper-V physical host to another without any disruption of service or perceived downtime. Moving running VMs without downtime using Hyper-V live migration:

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 lmigration across different CPU versions within the same processor family (for example, ”Intel Core 2-to-Intel Pentium 4” or “AMD Opteron-to-AMD Athlon”), enabling migration across a broader range of server host hardware.

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.

Because of the architecture of CSV, there is improved cluster node connectivity fault tolerance that directly affects 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.

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.

Even with all the efficiency gained from virtualization, VMs still need to be managed. The number of VMs 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.

The new Hyper-V leverages several new networking technologies contained in Windows Server 2008 R2 to improve overall VM networking performance.

Hyper-V in Windows Server 2008 R2 adds enhancements that reduce virtual machine 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. New Hyper-V VMs also consume less power by virtue of the new Core Parking feature implemented in Windows Server 2008 R2.

In Windows Server 2008 R2 there are three new networking features that improve the performance of virtual networks. Support for Jumbo frames, previously available in non-virtual environments, has been extended to work with VMs. This feature enables VMs to use Jumbo Frames up to 9014 bytes if the underlying physical network supports it. Supporting Jumbo frames reduces the network stack overhead incurred per byte and increases throughput. In addition, there is a significant reduction of CPU utilization due to the fewer number of calls from the network stack to the network driver.

TCP Chimney, which allows the offloading of TCP/IP processing to the network hardware, has been extended to the virtual environment. It improves VM performance by allowing the VM to offload network processing to hardware, especially on networks with bandwidth over 1 GB. This feature is especially beneficial for roles involving large amounts of data transfer, such as the file server role.

The Virtual Machine Queue (VMQ) feature allows physical computer network interface cards (NICs) to use direct memory access (DMA) to place the contents of packets directly into VM memory, increasing I/O performance.

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.

Broad support for simultaneously running different types of operating systems, including 32-bit and 64-bit systems across different server platforms, such as Windows, Linux, and others.

Hyper-V includes new virtual switch capabilities. This means virtual machines can be easily configured to run with Windows Network Load Balancing (NLB) Service to balance load across virtual machines on different servers.

With the new virtual service provider/virtual service client (VSP/VSC) architecture, Hyper-V provides improved access and utilization of core resources, such as disk, networking, and video.

Hyper-V provides the ability to take snapshots of a running virtual machine so you can easily revert to a previous state, and improve the overall backup and recoverability solution. 

Standards-based Windows Management Instrumentation (WMI) interfaces and APIs in Hyper-V enable independent software vendors and developers to quickly build custom tools, utilities, and enhancements for the virtualization platform.