<strong>Failover Clustering</strong>
In order to get all of the benefits of High Availability and similar features that require the use of shared storage between your Hyper-V hosts in a “cluster”, you must installed the Failover Clustering role on your Hyper-V hosts. This is, as the name indicates, what allows you the ability to “cluster” the hosts together.

Installing this role is just as easy as installing the Hyper-V role-- simply check the box under the Features in the add new roles/features wizard, and it'll run through the install. It's worth noting that the server you are installing this role on MUST be a member of the domain at the time of installation, or it won't go through with the install.

Once the feature is installed and the server is rebooted, you must run through the Pre-Clsuter Validation report, which will check out the hardware, drivers, etc. and alert you to anything that would prevent your cluster from working and/or being supported by Microsoft.

From here, you create a new cluster, give it a name, an IP address, etc. and add your single node into it. Rinse and repeat to add additional hosts.

Any network interfaces that have an IP address assigned to them (as is usually the case for interfaces or NIC teams that are used for management, cluster heartbeats, or iSCSI storage access) will show up as Networks in the Failover Clustering management interface. You can rename them to be more readable, and as long as the subnets stay the same across hosts, all hosts can share those networks without having to do anything special to keep the names consistent.

Jumping ahead to the future state of a common Hyper-V 2012 deployment WITHOUT System Center Virtual Machine Manager (SCVMM, which we'll mention in more detail later), the Failover Clustering management utility is where you will be able to migrate your virtual machines across nodes in your cluster.

Clustered Shared Volumes
To briefly define a “Clustered Shared Volume” to someone familiar with ESXi, consider it the equivalent of a VMFS datastore. It's essentially a unit of storage that is able to be accessed by multiple hosts at the same time, just like the VMware File System (VMFS) allows. It's similar to a clustered file system given the nature of its functionality, but it still runs Microsoft's well known NTFS as the underlying file system.

In order to add a CSV to a cluster, you present the storage as appropriate for your configuration and vendor's best practices, and it becomes available to the “Add Disk” wizard, as available and cluster-capable storage. Once it has been added, you can then right click it and select “Add to Clustered Shared Volume”.

NEED MORE INFO ON THE CLUSTER/STORAGE CONFIUGRATION, ESPECIALLY ON THE PROCESS TO ADD TO AN EXISTING CLUSTER AS WELL AS WHAT ALLOWS IT TO MOUNT UNDER C: OR OTHER PATHS

Storage
One of the advantages VMware/ESXi still has over Hyper-V is its built-in, native multipathing capability. For those unfamiliar, NMP allows the use, failover, failback, and in some cases, load balancing/load distribution of all the paths to your shared storage array.

The only equivalent utility natively available in Hyper-V 2012 is the MPIO driver, which combines its use with the built-in iSCSI initiator.

For those who are familiar with and have used the NMP beyond “install and let it run”, you know how incredibly valuable and efficient it is in nearly all deployment use cases (aside from NFS, which is a different beast entirely).

It's worth noting that leading storage vendors like EMC provide their own multipathing plugins or software that you can use to provide highly enhanced, optimized path management, load balancing, and failover, In EMC's case, this software is their PowerPath V/E, or Virtual Edition, and it makes a great add-on to any Hyper-V 2012 + EMC Storage deployment.

Performance
Without having any kind of head-to-head comparison or test to benchmark the two, the performance on our Hyper-V host seemed to be very good, and on par with what we're accustomed to seeing with ESXi. One area that we saw discussed a lot on the forums, and mentioned a few times by customers, was the increased overhead of having the hypervisor install in a “not-really-baremetal” model, as is the case in Hyper-V 2012. If you installed 2012 in the full GUI mode, it'll use more memory than in the Core deployment, and if you're trying to squeeze out every bit of memory from your hardware possible, we'd suggest going the Core route.

That aside, Microsoft has referenced several times that the performance of certain software deployments, namely RDS and Citirx XenApp, is greater on Hyper-V 2012 than the other hypervisors. We are not able to verify the results, but would understand if it was true, as it'd be a safe assumption Microosft would best know how to enhance performance of a Microsoft product (RDS, which XA also uses).
Feature Parity (Need lots of research here)
If you were to believe the marketing folks, Hyper-V and vSphere 5.1 would have feature parity-- that is to say, every feature available in vSphere 5.1 is also available in Hyper-V 2012. In our experience, this is not the case, though it is pretty darn close.

One of the “features” that our customers find very valuable and use frequently, is the ability to “hot-grow” a virtual disk (VHD/VHDX in Hyper-Vs case, a VMDK in Vmware/ESXi's), and then extend it in the guest operating system. This is something that you still cannot do in Hyper-V 2012. In order to grow a virtual disk, you must shut the VM down (incurring downtime), set the size desired, and then boot it back up. In ESXi, you simply edit the VM while it's running, and the storage is immediately available to the guest.

This was one that had us scratching our heads, as one would think if VMware could do this, Microsoft certainly could, at least for their own operating systems.

While it's not something that would stop us from deploying or recommending Hyper-V to customers that fit its use case, it's definitely something that we hope to see in the very near term, as it's as close to a “must-have” feature as a non-must-have feature can get.

Management
For those looking at Hyper-V 2012 but not the System Center 2012 suite, you will find that you must use multiple management interfaces to be able to manage your virtual workloads. This includes using Hyper-V manager to directly manage the VMs, access their consoles, edit their settings, etc. as well as using the Failover Clustering interface to manage the Clustered Shared Volumes, migrate virtual machines from node to node, and perform certain maintenance tasks.

In this model, Hyper-V is less expensive, nearly equal in feature set, but a little bit of a pain to manage. Now if you purchase System Center 2012 (which in the 2012 version no longer comes as one off products, but rather the entire suite), you gain access to the Virtual Machine Manager, which is much closer in comparison to VMware's vCenter server.

Some customers choose to spring for System Center, as the other products in the suite have tremendous value above and beyond the benefits of simplified virtual workload management via VMM, and this provides a huge bang of the buck. Others have deployed Hyper-V 2012 as a way to reduce their overall costs, and decide to stick with the multiple management interfaces. Either way works, though we'd strongly suggest evaluating System Center before eliminating it from consideration (and again, not just for VMM).

Conclusion
Hyper-V 2012 makes strong competition in the current hypervisor market. Its price point allows it to win while competing on price, and its growing feature set and capabilities allow it to put up a heck of a fight in its usefulness and utility for customers-- proving its value to all areas of an organization, from the CFO/CTO, to the system admins responsible for keeping the systems online.

The Datacenter Edition of Server 2012 includes the ability to host as many Windows Server VMs as the hardware can handle for no additional cost, meaning you only buy one license for your host (assuming 2 physical processors), and no longer need to pay for a server license each time you spin up a new VM.

Combine that with the ability to Live Migrate, Storage Live Migrate, Live Migrate without shared storage (known as “Shared Nothing Live Migration”), Replication/DR capabilities via the Hyper-V Replicas, and automation through the use of PowerShell and System Center, and you've got something that should be here to stay and compete for a long time.

Customers will benefit from Microsoft stepping it up and proving to be stiff competition for VMware as is almost always the case in the open marketplace. Not only does this have the potential to drive down prices, it should help keep the pace of feature innovation high, as any stagnation from one vendor could lead to lost opportunities in our fast-pace and ever changing technology industry.

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