Hyper-V Live Migration: A Step-by-Step Guide

Live migration is probably the most important technology that Microsoft has added to Hyper-V in Windows Server 2008 R2. It enables virtual machines (VMs) to be moved between Hyper-V hosts with no downtime. Using live migration, you can migrate all VMs off the Hyper-V host that needs maintenance, then migrate them back when the maintenance is done. In addition, live migration enables you to respond to high resource utilization periods by moving VMs to hosts with greater capacities, thereby enabling the VM to provide end users with high levels of performance even during busy periods.
      Live migrations can be manually initiated, or if you have System Center Virtual Machine Manager 2008 R2 and System Center Operations Manager 2007, you can run automated live migrations in response to workload. You need to complete quite a few steps to set up two systems for live migration, and I’ll guide you through the process. First, I’ll explain how live migration works. Then I’ll cover some of the hardware and software prerequisites that must be in place. Finally, I’ll walk you through the important points of the Hyper-V and Failover Clustering configuration that must be performed to enable live migration.

How Live Migration Works

Live migration takes place between two Hyper-V hosts. Essentially, the VM memory is copied between Hyper-V hosts. After the memory is copied, the VM on the new host can access its virtual hard disk (VHD) files and continue to run. Both hosts access shared storage where the VM’s VHD files are stored. When you initiate a live migration, which Figure 1 shows, the following steps occur:

      1. A new VM configuration file is created on the target server.
      2. The source VM’s initial memory state is copied to the target.
      3. Changed memory pages on the source VM are tagged and copied to the target.
      4. This process continues until the number of changed pages is small.
      5. The VM is paused on the source node.
      6. The final memory state is copied from the source VM to the target.
      7. The VM is resumed on the target.
      8. An Address Resolution Protocol (ARP) is issued to update the network routing tables.

Requirements for Live Migration

On the hardware side, you need two x64 systems with compatible processors. It’s best if the host processors are identical, though it’s not required. However, they do need to be from the same processor manufacturer and family—you can’t perform a live migration when one host has an AMD processor and the other host has an Intel processor. Learn more about Hyper-V processor compatibility in the Microsoft white paper “Virtual Machine Processor Compatibility Mode.”
      In addition, each of the servers should be equipped with at least three NIC cards, running at 1GHz: one for external network connections, one for iSCSI storage connectivity, and one for node management. Ideally, you’d have another NIC dedicated to the live migration, but the live migration can also occur over the external network connection—it will just be a little slower. It’s important to note that if you’re implementing a server consolidation environment, you will want additional NICs for the network traffic of the VMs.
      On the software side, all the nodes that take part in live migration must have Server 2008 R2 x64 installed. This can be the Standard, Enterprise, or Datacenter editions. Live migration is also supported by the Hyper-V Server 2008 R2 product. In addition, the Hyper-V role and the Failover Cluster feature must be installed on all servers participating in live migration.
      You also need shared storage, which can be either an iSCSI SAN or a Fibre Channel SAN. In this example, I used an iSCSI SAN. Be aware that the iSCSI SAN must support the iSCSI-3 specifications, which includes the ability to create persistent reservations, something that live migration requires. Some open-source iSCSI targets such as OpenFiler don’t have that support at this time. If you’re looking to try this for a local test and don’t want to buy an expensive SAN, you might want to check out the free StarWind Server product at http://www.starwind.com/.

Failover Cluster Networking Configuration

Failover clustering is a requirement for live migration. You can live-migrate VMs only between the nodes in the failover cluster. The first step in creating a failover cluster is to configure the networking and storage. You can see an overview of the network configuration used to connect the Windows servers in the cluster to the external network and to the shared storage in Figure 2.

      In Figure 2 the servers are using the network with the subnet of 192.168.100.xxx for client connections. The iSCSI SAN is running on an entirely separate physical network which was configured using the 192.168.0.xxx IP addresses. You can use different values for either of these IP address ranges. I selected these values to more clearly differentiate between the two networks. Ideally, you would also have additional NICs for management and an optional live migration connection, but these aren’t strictly required. Live migration can work with a minimum of two NICs in each server.

Installing Ubuntu Server 10.10 on Hyper-V

After downloading the bits from http://www.blogger.com/goog_2019813541 I created a quad-processor virtual machine with a non-legacy network adapter.
Installation was fairly straight forward:

However – Ubuntu does not have the Hyper-V enlightened network drivers enabled by default – so the installation complains about not being able to find any network adapters:

But I just ignored that and moved along with the install:

I chose the default packages for setting up a LAMP server:

The install finished and I was dropped at the login prompt:

A cool thing to note was that at this stage I could already shut down the virtual machine by using the shutdown button on the Virtual Machine Connection window, so part of the integration services are already running.  You can also see that all four virtual processors are there and working:

Getting the Hyper-V drivers up and running at this point in time is actually relatively simple.  The first thing you need to do is to edit /etc/initramfs-tools/modules and add the following lines to the end of it:
hv_vmbus
hv_storvsc
hv_blkvsc
hv_netvsc
Once you have made these changes you will need to run “update-initramfs –u” and reboot.  You will now have the Hyper-V drivers for storage and networking loaded:

You can confirm that these drivers are loaded by running “lsmod” after the reboot:

The final thing you need to do is to configure networking (because that step was skipped during installation).  The first thing to do is to run “ifconfig –a” to find out what name your network adapter has been given.  In my case it was “eth0” – but this is not always the name it will get.  Once you know the name you will need to edit /etc/network/interfaces and add the following to the end of the file:
For DHCP (what I did):
Auto eth0
iface eth0 inet dhcp
For a Static IP address:
Auto eth0
iface eth0 inet static
address [insert your IP address]
netmask [insert your netmask]
Gateway [insert your gateway address]

Like this:

One more reboot and running “ifconfig” should confirm that everything is working:

And in my case I could also confirm that the website was accessible from my parent partition as well:

 Ubuntu Server 10.10 running under Hyper-V with full integration services using nothing other than what is included on the Ubuntu install media.

Hyper-V: How To Initiate a Live Migration using Windows PowerShell

You can initiate Live migration using Windows PowerShell scripts for failover clustering. This is one of the steps documented in Hyper-V: Using Live Migration with Cluster Shared Volumes in Windows Server 2008 R2 (http://technet.microsoft.com/en-us/library/dd446679(WS.10).aspx#BKMK_initiateLM)

 To initiate a live migration using Windows PowerShell

1. Open Windows PowerShell. Click Start, point to All Programs, click Windows Powershell 2.0, and then click Windows Powershell 2.0.

The Failover Clustering feature must be installed on the computer on which you are starting the Windows PowerShell session. Or, you can use Remote Server Administration Tools for Windows® 7 to run the PowerShell session.

1. To install the Failover Clustering feature, type:

Add-Module FailoverClusters

1. Type:

Get-Cluster "<Cluster Name>" | Move-ClusterVirtualMachineRole -Name "<VM group name>" -Node "<Destination node name>"
Where:

• <Cluster Name> is the name of the cluster that the virtual machine is included in.
• <VM group name> is the virtual machine resource group.
• <Destination node name> is the name of the destination node to which you would like to move the virtual machine using live migration.

Understanding and comparing the Hyper-V architecture

Hypervisor architecture

History of virtualization at Microsoft

Everything began in February 2003 when Microsoft acquired a company that was already on the market since 1988 called Connectix. This company had a solution that could virtualize operating systems. For those who didn't know was surprising, because it was possible to do multiple tests of the functionality of the operating system (OS), but a virtual form within an existing OS. What is interesting is that virtualization technology is not new. True virtual environments, already existed in large Main Frames of the 1960s that could simulate a virtual environment, several virtual machines as the IBM model I44. In September 2004 Microsoft released Virtual Server 2005, a server with support for virtual machines (VM), but this had some hardware limitations, virtual systems could use only one processor x86 and maximum 3.6 GB of memory per VM. Running in parallel with these solutions virtual Intel and AMD launched its processors with hardware virtualization support, baptized of Intel-VT and AMD-V. Virtual Server 2005 R2 SP1 was launched and has already provided support to the new processor technologies, providing better performance, however all hardware call was sent from VMs to the virtual machine monitor (VMM), it forwarded these calls to the host operating system and then to the Windows kernel. Only after that the VM Hardware being accessed in this way, a processor switching between physical and virtual machine. It was for this reason that the Virtual Server 2005 does not used 100% of the power provided by the hardware virtualization from Intel and AMD.

In Windows 2008 Microsoft released Hyper-V and the Hyper-V Server. The latter would be a free version of the operating system only with Hyper-V role enabled. Hyper-v supports x86 and x64 VM, and 64 GB of memory and up to 4 processors per virtual machine, using the entire capacity hardware virtualization. In the table below is apparent difference between solutions:

Table 1 – differences between virtual server, hyper-v and hyper-v Server

Compared to its predecessor Virtual Server 2005, the Hyper-V differential associated with hardware virtualization are VMs with more memory and processor support, so the speed and security.

Virtual Machine Monitor (VMM)

To explain in a way more advanced and technical difference between virtualization types used by the virtual server and hyper-v, is important to understand a little of the VMM.

It is responsible for the creation, preservation, access to system resources and VM management. There are three types of implementation: VMM type 2 hybrid VMM and VMM type 1.

VMM type 2                             VMM hybrid                                  VMM type 1

Figure 1 – types of VMM

VMM type 2 runs above the host operating system. The hybrid type runs parallel to the host system, type this used by Virtual Server 2005 R2, which has used the technology of AMD-V and Intel-VT, but without the hypervisor. The third, type 1, is a Hypervisor-based solution, used by the hyper-v, providing performance and with a series of components for communication of VMs to hardware.

Structure of Hypervisor

Windows Server 2008 with Hyper-v provides a structure for the Hypervisor-based virtualization of type 1 (VMM), I believe that this should not be news to anyone since it is normal to read or hear this in almost every place where the subject is Microsoft Virtualization. When you install Windows Server 2008 the Hyper-V is not installed automatically. The OS without Hyper-v has direct access to hardware and Hypervisor structure does not exist, as Figure 2.

After operating system installation you need to add the function of hyper-v in Server Manager (this function is only available in Windows Server 2008 x 64).

Figure 2 – Windows 2008 without Hyper-V

After installation of Hyper-V and rebooting the machine, OS suffers several amendments. The file responsible for Windows boot (Winload.exe) loads the driver hvboot.sys. This driver checks which processor is running, and whether it supports virtualization. After this process is loaded the hypervisor image file (Hvix64.exe for Intel-VT or Hvax64.exe to AMD -V). Only after this the system boots, thereby creating a single standard called Parent Partition, where you made the first virtualization and it runs Windows 2008. Sounds strange, but is that the operating system that you raise after the hyper-v virtual also was installed. The virtual machines that are added after the hyper-v are created in partitions call Child Partitions. Is the Hypervisor that manages these partitions and control access them to hardware.

Hardware virtualization

Another interesting approach is subject to hardware virtualization. Without this there are only 4 specific hardware of rings, called Rings processor, which define the level of access privilege to the processor. The privilege is the ring 0, used by the Windows kernel and Ring 3 is typically used in user level, amounting to a total of 4: ring 0, 1, 2 and 3.

When installing the hyper-v is created a ring that runs on a privileged mode called privileged or ring -1. This ring causes the hypervisor rode in a greater privilege that the Windows kernel allowing any operating system continue to be used for ring 0 and users application running in ring 3. In Figure 2 you can analyze Parent and Child partitions, in addition to processing rings.

Figure 3 – Hypervisor, Rings and partitions

Virtualization Stack

All creation and management of virtual machines of hyper-v are made by a series of virtual devices and software components that work together called Virtualization Stack used in both the Parent and Child partition. Some of them are: Virtualization Service Provider (VSP), Virtualization Service Client (VSC) Virtualization Infrastructure driver (VID) and virtual machine bus (VMBus). This series of software and components work with Hyper-v management in conjunction with the hypervisor. The VSP is a software component that is in the Parent partition and that controls I/O requests on behalf of the virtual machines. Already the VMBus is responsible for data transfer and delivery of services between Parent and Child partitions for a dedicated channel available between the VSCs and VSPs. The VSC uses the VMBus for the communication of the VSP partitions Child up to the functioning of synthetic drivers that run on the Child partitions.

The VID uses some APIs for communication between the Parent partition to the Hypervisor. The access and the instructions of the Parent partition APIs to Hypervisor are called Hypercalls. The VID is applied in two levels: kernel-level with the file VID.sys in ring 0 and User level by VID.ll file in Ring 3.

Hyper-V 'n' its Key Feature.

Microsoft Windows Server 2008 R2 Hyper-V builds on the architecture and functions of Windows Server 2008 Hyper-V by adding multiple new features that enhance product flexibility. The adoption of virtualization in the enterprise has increased flexibility in deployment and life cycle management of applications. IT professionals deploy and use virtualization to consolidate workloads and reduce server sprawl. Additionally, they deploy virtualization with clustering technologies to provide a robust IT infrastructure with high availability and quick disaster recovery. Even so, customers are looking for more flexibility.

Live Migration

 Windows Server 2008 R2 Hyper-V provides greater flexibility with live migration. Live migration is integrated with Windows Server 2008 R2 Hyper-V and Microsoft Hyper-V Server 2008 R2. With Hyper-V live migration, you can move running virtual machines (VMs) from one Hyper-V physical host to another, without any disruption or perceived loss of service. IT professionals increasingly look to live migration to create a dynamic and flexible IT environment that responds to emerging business needs. Live migration provides the core technology required for dynamic load balancing, VM placement, high availability for virtualized workloads during physical computer maintenance, and reduced data center power consumption.

Dynamic Memory

New in Windows Server 2008 R2 with SP1, Dynamic Memory enables customers to better utilize the memory resources of Hyper-V hosts by balancing how memory is distributed between running virtual machines. Memory can be dynamically reallocated between different virtual machines in response to the changing workloads of these machines. Dynamic Memory thus enables more efficient use of memory while maintaining consistent workload performance and scalability. Implementing Dynamic Memory means that higher levels of server consolidation can be achieved with minimal impact on performance. Dynamic Memory also means larger numbers of virtual desktops per Hyper-V host for VDI scenarios. The net result for both scenarios is more efficient use of expensive server hardware resources, which can translate into easier management and lower costs. 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.

Core Scenarios for Hyper-V

Hyper-V provides a dynamic, reliable, and scalable virtualization platform combined with a single set of integrated management tools to manage both physical and virtual resources, enabling you to create an agile and dynamic data center. Hyper-V enables:

Server Consolidation

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 and Disaster Recovery

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

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.

Dynamic Data Center

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.

Expand Desktop Deployment Options with VDI

Much of the interest in virtualization solutions is in the server world. However, equally exciting advances are being made in server-based desktop virtualization, where processing happens on a server optimized for capacity and availability while graphics, keyboard, mouse, and other user I/O functions are handled at the user’s desktop.

Windows Server 2008 R2 Remote Desktop Services extends the functionality of Session Virtualization from delivering session-based desktops and applications to also enabling the delivery of virtual desktops in a virtual desktop infrastructure (VDI). With Remote Desktop Services, both virtual and session-based desktops and applications are now available on the Windows 7 Start menu right alongside programs that are installed locally.

VDI with Windows Server 2008 R2 with SP1 benefits from a rich end user experience with support for rich media and USB devices with Microsoft RemoteFX as well as a great better together story with Windows 7 as the guest OS due to increased VM density with Dynamic Memory and near-invisible integration of virtualized desktops in Windows 7.

Key Features of Hyper-V

Windows Server 2008 R2 Hyper-V 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 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.

Live Migration

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:

• Provides better agility. Data centers with multiple Hyper-V physical hosts can move running VMs to the best physical computer for performance, scaling, or optimal consolidation without affecting users.
• Reduces costs and increases productivity. Data centers with multiple Hyper-V physical hosts can service those systems in a controlled fashion, scheduling maintenance during regular business hours. Live migration makes it possible to keep VMs online, even during maintenance, increasing productivity for users and server administrators. Data centers can now also reduce power consumption by dynamically increasing consolidation ratios and powering off un-used physical hosts during lower demand times.

Increased 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 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.

Cluster Shared Volumes

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 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.

Improved Management of Virtual Data Centers

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.

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.

Increased Performance and Reduce Power Consumption

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.

Enhanced Networking Support

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.

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.

Broad OS Support

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.

Network Load Balancing

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.

New Hardware Sharing Architecture

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.

Virtual Machine Snapshot

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. 

Extensible

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.

Hyper-V provides a reliable virtualization platform that enables customers to virtualize their infrastructure and reduce costs. It has thin microkernelized hypervisor architecture with minimal attack surface and is available as a Server Core role. With System Center integrated management tools, customers can use a single set of tools to manage both their physical and virtual resources. It easily plugs into customers’ IT infrastructure, as they can leverage their existing patching, provisioning, management and support tools, and processes. It provides great value, as it is available as a feature of Windows Server 2008 R2, and customers can leverage the breadth of solutions from Microsoft partners, existing IT Pro skill sets, and comprehensive support from Microsoft.

 

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 virtualized data centers
• Improved management of virtualized data centers
• Increased performance and hardware support for Hyper-V virtual machines
• Improved virtual networking performance
• 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 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 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 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.
• 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 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.

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, and 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 and new scenarios in complex Microsoft Exchange and Microsoft 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.

• Increased Performance and Hardware Support for Hyper-V Virtual Machines
  Hyper-V in Windows Server 2008 R2 adds new 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. New Hyper-V VMs will also consume less power by virtue of the new Core Parking feature implemented in 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 TCP Offload support and the use of Jumbo Frames. TCP Offload 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 extends this functionality into the virtual world. This benefits both CPU and overall network throughput performance, and it’s fully supported by Live Migration.

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.

Key Features of Hyper-V in Windows Server 2008 R2 and Windows Server 2008

Hyper-V as a part of Windows Server 2008 R2 (Standard, Enterprise, and Datacenter) and of x64 editions of Windows Server 2008 (Standard, Enterprise, and Datacenter) includes the following capabilities:

High availability

Hyper-V includes support for host-to-host connectivity and enables you to cluster all virtual machines running on a host.

Server Core role

Hyper-V is available as a role in a Server Core installation of Windows Server 2008 and Windows Server 2008 R2.

Integrated into Server Manager

Hyper-V is integrated into Server Manager by default and customers can now enable the role within Server Manager.

Live Backups with VSS

Hyper-V includes support for Volume Shadow Copy Services (VSS) to enable you to take Live Backups of running virtual machines in terms of snapshots.

VHD tools

Hyper-V also includes support for VHD tools to enable compaction, expansion, and inspection of VHDs created with Hyper-V.

Linux integration components

The Linux Integration Components for Hyper-V improve the performance of Linux Guests by providing driver support for synthetic devices and fastpath boot support for Hyper-V. The Linux Integration Components support SUSE Linux Enterprise Server 10 Service Pack 2 and above, as well as Red Hat Enterprise Linux 5.2 and above.

Download Linux Integration Components for Windows Server 2008 Hyper-V R2.

VM manageability

Enables customers to easily import or export virtual machine settings to take backups of configurations and to be able to clone the virtual machine characteristics across different hosts.

Improved performance

Hyper-V includes several fixes to improve performance. All new Windows Server 2008 and Windows Server 2008 R2 virtual machines will now automatically include the integration components.

Improved access control with AzMan

Hyper-V includes support for Authorization Manager (AzMan) to enable Role-Based Access Control models for better administration of the Hyper-V environment with increased security.

Remote management

Hyper-V supports remote management and also provides a Hyper-V MMC only installation option for a separate management node.

Increased virtual SCSI support

Hyper-V now includes support for up to four virtual SCSI controllers per virtual machine enabling broader disk support.

Increased memory support

Hyper-V supports up to 64 GB of memory per virtual machine.

Quick Reset

Hyper-V provides administrators the option to quickly Reset Checkboxes and Delete saved credentials that are used to connect to virtual machines.