Review: Microsoft Hyper-V 2012 narrows the gap
Windows Server 2012 Hyper-V combines easy setup and management with new features that lower the entry barrier to highly available virtualization clusters
With the release of Windows Server 2012, Hyper-V gains increased scalability in terms of both raw specs and features that make larger environments easer to manage. Hyper-V 2012 pushes the limits to 4TB of RAM per host and 64 nodes per cluster, and it adds advanced features such as a virtual switch, a virtual SAN, and live storage migration that were previously available only from VMware. It also includes native clustering capability, so you have the ability to build a highly available virtual machine cluster with commodity hardware and two OS licenses.
Although Microsoft has made great strides in many feature areas, there is still a fairly substantial gap between Hyper-V and VMware vSphere at the high end. VMware has many features focused on service providers, whether they're companies offering services for sale or large enterprise IT departments delivering services to business units within the company. Hyper-V 2012 does not have anything like VMware's vSphere Storage DRS (Distributed Resource Scheduler), for example, where you can provision different classes of storage based on a set of requirements to include cost and performance. Hyper-V also lacks many of the new virtual data center features recently introduced by VMware. (See my review of VMware vSphere 5.1.)
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That said, Hyper-V 2012 also introduces many new features that make it more attractive to small and midsized companies where cost is a significant driver. The new capabilities in SMB 3.0 allow anyone to stand up an HA Hyper-V cluster using low-cost servers and commodity SAS disk drives. In the past you would have been required to purchase a high-dollar storage system to get the same level of reliability, and you would have needed to buy the virtualization software from a vendor other than Microsoft. Low-cost HA clustering alone will make IT managers think twice about spending scarce IT budget dollars on additional software when Windows Server 2012 comes with Hyper-V in the box.
In addition to examining features and manageability, I ran a few performance tests. Using the Sandra 2013 benchmarks for a Windows 32-bit client, I tested Windows VM performance under vSphere 5.0, vSphere 5.1, Hyper-V under Windows Server 2008 R2, and Hyper-V under Windows Server 2012. The server hardware used for this review was a Dell PowerEdge R715 with dual AMD Opteron 6380 CPUs, 64GB of memory, and two Seagate ST9300605SS 10K 300GB SAS drives configured as a RAID1 array.
Installation and configurationHyper-V 2012 couldn't be any easier to install in Windows Server 2012. Simply choose the Hyper-V role from the Server Manager application, click through a few screens, and you're done. Be aware that the install will require a reboot of your server. You'll need to go through a few basic configuration steps before you can actually deploy VMs on your new Hyper-V installation. All Hyper-V 2012 VMs require a virtual switch connection in order to communicate over the network. Because a virtual switch must be connected to an underlying network interface for a physical connection, you must configure this connection after Hyper-V is installed.
While included in Windows Server 2012, Hyper-V 2012 is also available in a free stand-alone version. This product essentially installs a server-core version of Windows Server 2012 with a minimal user interface. It's intended to be managed remotely, with just a few options and controls available from the console. These include details such as changing the computer name, networking configuration, enabling remote desktop, and powering down the system. Adding a Hyper-V Server 2012 host to the management console on another Windows Server 2012 machine requires merely a right-click and the entry of the Hyper-V server's IP address.
New and improvedA number of new capabilities introduced in Hyper-V 2012 extend existing features. For example, live migration of running VMs, which previously required shared storage, can now be done in a nonclustered environment. This feature is called "shared nothing migration" in some circles. Live storage migration -- a new feature that aims at parity with VMware -- makes it possible to move the virtual hard disks in use by a running VM to a different storage device. These two features combined make it possible to move running VMs between any connected machines on a domain.
Hyper-V Replica, which provides unlimited, host-to-host replication of virtual machines without shared storage, brings Microsoft up to par with other virtualization vendors in the area of redundancy. The ability to store Hyper-V disks on SMB shares is yet another feature that delivers a new level of resiliency in the form of Cluster Shared Volumes for SMB file stores. Cluster Shared Volumes essentially eliminates the need for high-cost storage to deploy an HA virtualization solution. The new Hyper-V Extensible Switch provides a platform upon which networking vendors can build new functionality. Hyper-V switch extensions might include network-based virus protection or intrusion detection solutions, for example.
On the numbers front, there are gains in the amount of memory an individual guest can support (1TB vs. 64GB in Windows Server 2008 R2), logical processors per host (320 vs. 64), and nodes per cluster (64 vs. 16). The total number of virtual processors per host is now 2,048, up from 512 in Windows Server 2008 R2. A single host can now support up to 1,024 active VMs as opposed to 384 in the previous release. Support for Non-Uniform Memory Access (NUMA) inside virtual machines is new to Hyper-V 2012 as well.
Managing Hyper-V 2012Microsoft has two basic paths for managing Hyper-V 2012 out of the box, using either the graphical user interface Hyper-V Manager or PowerShell. Either way, the work gets done with PowerShell commands and scripts behind the scenes. The real power behind both management paths is the ability to manage multiple machines from a single console. Hyper-V Manager can manage any number of different Hyper-V hosts, all from within the same console. Even for small deployments, managing Hyper-V through Hyper-V Manager is much more efficient than remotely logging into each machine. The wizard-based approach to guiding you through most of the management tasks helps fledgling Hyper-V administrators get the job done.
PowerShell 3.0 is without question one of the other huge productivity gains for IT administrators responsible for supporting Windows Server 2012. With something like 2,430 new "cmdlets," there isn't an area of managing a Windows Server 2012 deployment without some support through PowerShell. With respect to Hyper-V 2012, there are upward of 140 unique cmdlets for managing all aspects of creating, provisioning, and running VMs. That number also includes cmdlets for managing the virtual network switch and other Hyper-V 2012 configuration parameters.
The next level of VM management comes in the form of Microsoft's System Center Virtual Machine Manager (SCVMM). SCVMM 2012 is the latest version but does not support Windows Server 2012 unless you apply Service Pack 1. Microsoft does offer a fully functional Hyper-V instance of SCVMM 2012 SP1 that includes the required SQL Server back end. You can install this on a Hyper-V 2012 host and manage other Windows Server 2012 systems once the configuration is complete. SCVMM 2012 is definitely the way to go for any organization with a large number of VMs.
Performance gainsHyper-V 2012 includes a number of improvements in the area of performance. As you can see from the comparative table, which shows Sandra 2013 test results for a 32-bit Windows 7 SP1 VM, the most obvious is in the area of the crypto bandwidth tests. Previous versions of Hyper-V did not support AES-NI instructions in Intel's Westmere CPUs or in the AMD Bulldozer CPUs. Hyper-V 2012 provides this support, as the numbers clearly show. Almost across the board, my Sandra results showed performance of Hyper-V 2012 improved over Hyper-V 2008 and even VMware vSphere 5.1. (Note: I did not test performance of Linux VMs.)
Other areas of performance gain are hard to measure directly but are present nonetheless. These include the virtual SAN support, which allows you to connect a VM directly to a virtual Fibre Channel host bus adapter. This makes it possible to provision a VM with direct-attached storage to support specific workloads that in the past would have required a dedicated server. Another key improvement in the I/O area is new support for Single-Root I/O Virtualization. Allowing supporting physical network interfaces to be carved into multiple virtual NICs, SR-IOV improves the Hyper-V host's networking functionality and overall throughput.
Final analysisHyper-V 2012 combines significant management and usability improvements with solid performance, especially for the purpose of virtualizing many typical Windows workloads. New PowerShell cmdlets streamline the process of automating many of the tedious administration tasks previously requiring significant amounts of hands-on time. While there aren't any huge performance improvements from the individual guest perspective, the new I/O bandwidth features could represent significant areas for gains. When you couple that with other new OS features like SMB failover and clustering, you have the makings of a solid foundational product.
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