What's New in Hyper-V for Windows Server 2012

Applies To: Windows Server 2012

This topic describes the new and changed functionality of the Hyper-V role in Windows Server® 2012.

If you are looking for information about Windows Server® 2012 R2, see What’s New in Hyper-V for Windows Server 2012 R2. For information about Hyper-V on Windows Server® 2016 Technical Preview, see What's new in Hyper-V on Windows Server 2016 Technical Preview.

Role description

The Hyper-V role enables you to create and manage a virtualized computing environment by using virtualization technology that is built in to Windows Server 2012. Hyper-V virtualizes hardware to provide an environment in which you can run multiple operating systems at the same time on one physical computer, by running each operating system in its own virtual machine. For more information about Hyper-V, see the Hyper-V overview.

New and changed functionality

The following table lists functionality in Hyper-V that is new for this release or has been changed.

Client Hyper-V

The Hyper-V technology is now available in a desktop operating system version of Windows.

What value does this change add?

This change enables you to use Hyper-V without installing a server operating system. For more information, see Client Hyper-V.

Dynamic Memory

Dynamic Memory improvements include support for configuring minimum memory, and Smart Paging, which is a memory management technique to provide a reliable restart experience for virtual machines configured with less minimum memory than startup memory.

What value does this change add?

These changes can help you improve your hardware utilization by making it more practical to run more virtual machines on a single physical computer at the same time. Memory resources can be allocated to virtual machines more efficiently, because you can configure a virtual machine with less minimum memory than startup memory without having to plan for enough memory to be available to restart the virtual machine.

What works differently?

You can now configure a virtual machine with minimum memory, using either Hyper-V Manager or the Set-VMMemory cmdlet. Smart Paging reduces the risk that a virtual machine might not be able to restart if a restart is required when there is not enough available physical memory. Smart Paging uses disk resources as additional, temporary memory when more memory is required to restart a virtual machine than the amount of memory currently allocated to a virtual machine. To minimize the potential performance impact of Smart Paging, Hyper-V uses it only when all of the following occurs:

1. The virtual machine is being restarted.

2. There is no available physical memory.

3. No memory can be reclaimed from other virtual machines running on the host.

For more information about improvements to Dynamic Memory, see the Hyper-V Dynamic Memory Overview.

Hyper-V module for Windows PowerShell

Hyper-V module for Windows PowerShell includes more than 160 cmdlets to manage Hyper-V, virtual machines, and virtual hard disks.

What value does this change add?

The availability of built-in Hyper-V cmdlets makes it easier to automate various operations than was possible in previous versions of Hyper-V. The cmdlet names are consistent with other Windows PowerShell cmdlets (using verbs such as ‘Get’ and ‘Set’) which makes it easier for users familiar with Windows PowerShell to learn to use new cmdlets.

What works differently?

Hyper-V cmdlets are available after being installed. The cmdlets can be installed when you install the role, or as a feature available through the Remote Server Administration Tools. For more information, see Hyper-V Module for Windows PowerShell.

Hyper-V Replica

This feature enables you to replicate virtual machines between storage systems, clusters, and data centers in two sites to provide business continuity and disaster recovery.

What value does this change add?

This feature makes it easier and less expensive to plan and implement business continuity and disaster recovery solutions for your virtual machines.

What works differently?

You can use a built-in solution to configure virtual machines to be replicated to a second server running Hyper-V. For more information, see Maintaining Business Continuity of Virtualized Environments with Hyper-V Replica: scenario overview [Pillar Overview].

Importing of virtual machines

The import process has been updated to help you resolve configuration problems that would otherwise prevent a virtual machine from being imported. You also can import a virtual machine after copying the files manually, rather than exporting the virtual machine first.

What value does this change add?

The import process has been simplified and is more reliable.

What works differently?

Before this update was introduced, the import process copied a virtual machine and its files but did not check for configuration problems. Now, the import process has been redesigned to detect and help you correct certain configuration problems.

Live migration

It is now possible to perform a live migration in a non-clustered environment, as well as perform more than one live migration at the same time and use higher networks bandwidths.

What value does this change add?

These improvements provide more flexibility in moving a running virtual machine by making it easier and faster to perform live migrations.

What works differently?

You can now perform a live migration without setting up failover clustering and Cluster Shared Volumes. Live migration in a non-clustered environment is supported both when storage is kept on a central SMB share, and when the storage is local. You can complete migrations faster by using higher network bandwidths (up to 10 gigabits). You can also perform more than one live migration at the same time to quickly move many virtual machines. For more information, see Virtual Machine Live Migration Overview. For instructions on performing a live migration outside a cluster, see Configure Live Migration and Migrating Virtual Machines without Failover Clustering.

Resource metering

You can now track and gather data about physical processor, memory, storage, and network usage by specific virtual machines.

What value does this change add?

You can determine the resource usage of specific virtual machines. You can use this data to perform capacity planning, to monitor consumption by different business units or customers, or to capture data needed to help redistribute the costs of running a workload.

What works differently?

You can configure a virtual machine to measure the physical processor, memory, storage, and network usage, and then measure the usage periodically. For more information, see Hyper-V Resource Metering Overview.

Significantly increased scale and improved resiliency

This version of Hyper-V offers significantly larger compute and storage resources than was previously possible and improves the handling of hardware errors.

What value does this change add?

These features help ensure that you can configure large, high-performance virtual machines to support workloads that might need to scale up significantly.

What works differently?

The computer that runs Hyper-V in Windows Server 2012 can be configured with up to 320 logical processors and 4 terabytes (TB) of memory. Virtual machines can be configured with 64 virtual processors and 1 TB of memory. Improved handling of hardware errors increases the resiliency and stability of the virtualization environment. For more information, see Hyper-V scalability in Windows Server 2012 and Windows Server 2012 R2 and Hyper-V Support for Scaling Up and Scaling Out Overview.

Simplified authorization

The Hyper-V Administrators group is introduced and is implemented as a local security group.

What value does this change add?

This group can reduce the number of users that belong to the local Administrators group while providing users with access to Hyper-V.

What works differently?

The Hyper-V Administrators group is a new local security group. Add users to this group instead of the local Administrators group to provide them with access to Hyper-V. Members of the Hyper-V Administrators have complete and unrestricted access to all features of Hyper-V.

SR-IOV

This new feature allows you to assign a network adapter that supports single-root I/O virtualization (SR-IOV) directly to a virtual machine.

What value does this change add?

Use of SR-IOV maximizes network throughput while minimizing network latency as well as the CPU overhead required for processing network traffic.

What works differently?

You can provide a virtual machine with direct connectivity to a physical network adapter. For more information, see Hyper-V Support for Scaling Up and Scaling Out Overview.

Storage migration

Move the virtual hard disks used by a virtual machine to different physical storage while the virtual machine remains running.

What value does this change add?

This new feature makes it easier to manage the physical storage subsystems used by virtual machines.

What works differently?

It is no longer necessary to take a virtual machine offline to move, maintain, or upgrade the underlying physical storage.

Storage on SMB 3.0 file shares

Hyper-V now supports use of SMB 3.0 file shares to provide storage for virtual machines.

What value does this change add?

This new feature provides a new way to provide virtual machines with shared storage, without use of a storage area network (SAN).

What works differently?

You can specify a file share as the storage location for virtual machines. For more information, see Deploy Hyper-V over SMB.

Virtual Fibre Channel

This new feature allows you to connect directly to Fibre Channel storage from within the guest operating system that runs in a virtual machine.

What value does this change add?

This feature makes it possible to virtualize workloads and application that require direct access to Fibre Channel-based storage. It also makes it possible to configure clustering directly within the guest operating system (sometimes referred to as guest clustering).

What works differently?

This feature makes host bus adapter (HBA) ports available within the guest operating system. For more information, see Hyper-V Virtual Fibre Channel Overview.

Virtual hard disk format

The new format has been introduced to meet evolving requirements and take advantage of innovations in storage hardware.

What value does this change add?

The new format increases the maximum storage size per virtual hard disk, as well as improves the stability and efficiency of those disks.

What works differently?

A new virtual hard disk format (VHDX) supports up to 64 terabytes of storage. It also provides built-in protection from corruption stemming from power failures and prevents performance degradation on some large-sector physical disks. For more information, see Hyper-V Virtual Hard Disk Format Overview.

Virtual machine snapshots

After a virtual machine snapshot is deleted, the storage space that the snapshot consumed before being deleted is now made available while the virtual machine is running.

What value does this change add?

It is no longer necessary to shut down, turn off, or put the virtual machine into a saved state to recover the storage space.

What works differently?

Operations that keep the virtual machine and any remaining snapshots synchronized after deleting a snapshot now occur while the virtual machine remains running. After those operations are complete, the files that contained the snapshots (.avhd files) are deleted. Previously, those operations did not occur while the virtual machine was running or paused.

Virtual NUMA

A virtual NUMA topology is made available to the guest operating system in a virtual machine.

What value does this change add?

Newer operating systems and high-performance applications such as SQL Server include optimizations that recognize a computer’s NUMA topology to increase performance by considering NUMA when scheduling threads or allocating memory. The virtual NUMA feature makes it possible for the guest operating system and NUMA-aware applications running in the virtual machine (such as SQL Server) to take advantage of these performance optimizations.

What works differently?

A virtual NUMA topology is made available to the guest operating system. The default virtual NUMA topology is optimized to match the NUMA topology of physical computer.

Virtual switch

The architecture of the virtual switch has been updated to provide an open framework that allows third parties to add new functionality to the virtual switch.

What value does this change add?

This change enables Microsoft partners to extend the virtual switch by providing new functionality such as monitoring, forwarding, and filtering into the virtual switch.

What works differently?

The open architecture makes it possible to use extensions, which are implemented by using Network Device Interface Specification (NDIS) filter drivers and Windows Filtering Platform (WFP) callout drivers. These two public Windows platforms for extending Windows networking functionality are used as follows:

• NDIS filter drivers are used to monitor or modify network packets in Windows.

• WFP callout drivers allow independent software vendors (ISVs) to create drivers to filter and modify TCP/IP packets, monitor or authorize connections, filter IP security (IPsec)-protected traffic, and filter remote procedure calls (RPCs).

For more information, see the Hyper-V Virtual Switch Overview.

Sleep support

Sleep and hibernate are no longer disabled when the Hyper-V role is installed.

What value does this change add?

Computers running Hyper-V can be put into sleep or hibernate mode. This is particularly useful to users who are running Hyper-V on laptops computers.

What works differently?

When installing the Hyper-V role sleep and hibernate are no longer disabled. When entering sleep or hibernate Hyper-V will save running virtual machines. When coming out of sleep or hibernate Hyper-V will attempt to restart the virtual machines that were running before entering sleep or hibernate.

Sleep support

Sleep and hibernate are no longer disabled when the Hyper-V role is installed.

What value does this change add?

Computers running Hyper-V can be put into sleep or hibernate mode. This is particularly useful to users who are running Hyper-V on laptops computers.

What works differently?

When installing the Hyper-V role sleep and hibernate are no longer disabled. When entering sleep or hibernate Hyper-V will save running virtual machines. When coming out of sleep or hibernate Hyper-V will attempt to restart the virtual machines that were running before entering sleep or hibernate.

Removed or deprecated functionality

The following features and functionalities have been removed from this release of Hyper-V. Applications, code, or usage that depends on these features will not function in this release unless you employ an alternate method. For more information about removed or deprecated functionality in this release, see Features Removed or Deprecated in Windows Server 2012.

• Virtual machine (VM) Chimney, also called TCP Offload, has been removed. The TCP chimney will not be available to guest operating systems.

The following features and functionalities are deprecated starting with this release of Hyper-V. Eventually, they will be completely removed from the product. We recommend that you begin planning now to employ alternate methods for any applications, code, or usage that depend on these features.

• The WMI root\virtualization namespace is deprecated. The new namespace is root\virtualization\v2.

• Windows Authorization Manager (AzMan) is deprecated. You may need to use new management tools for virtual machines or redesign the authorization model you use.

See also

The following table provides additional resources for evaluating Hyper-V.