Microsoft Hyper-V Server 2012 Release Candidate Now Available

At Tech Ed 2012, Microsoft announced the newest version of what is, to me, a great but largely overlooked virtualization product: Hyper-V Server. Microsoft Hyper-V Server 2012 takes the strong feature set in Hyper-V Server 2008 R2 SP1 and updates it with the exact same important updates that are in the full Windows Server 2012 Hyper-V role. I sat down with Jeff Woolsey, Principal Program Manager Lead for Hyper-V, on the Tech Ed Expo floor to talk about what he’d just announced.

If you aren’t familiar with Hyper-V Server, you aren’t alone. It’s quite natural to assume that, like “freemium” software, the free version of Microsoft’s server virtualization solution has a cut-down feature set or is otherwise lobotomized compared to the full Windows Server Hyper-V role. You’d be mistaken. In both Windows Server 2008 R2 and Windows Server 2012, Hyper-V Server boasts the same features. What’s the difference between the two, then? The first is that Hyper-V Server runs with a simple command line interface rather than a full parent partition on the virtualization host server. This lack of an interface is rarely a problem because you really shouldn’t be managing a host server at its console anyway; you should be managing it remotely. And Hyper-V Server is remotely managed exactly the way you manage the full Hyper-V role, by using Hyper-V Manager in the Remote Server Administration Toolkit (RSAT) or System Center Virtual Machine Manager.

The second difference is in licensing. Unlike the full version, Hyper-V Server provides for no operating system environments (OSEs) to automatically license those Windows VMs on the host. Because of the way Microsoft virtualization licensing is designed, it’s more advantageous for most customers to purchase Windows Server Datacenter and get unlimited OSEs than use Hyper-V Server and purchase licenses separately. There are, however, several scenarios where Hyper-V Server is a perfect fit and you can reduce your operating costs by using it. First, let’s review a few of the highest-profile features in Windows Server 2012 Hyper-V.

Hyper-V 2012 Features

Last year, my colleague Mike Otey provided an overview of the wide range of significant features in Windows Server 2012 (then Windows Server 8) Hyper-V. To me, the feature with the broadest appeal to the widest array of environments is shared nothing (SNO) Live Migration. This is the ability to migrate a live VM from one Hyper-V host to another without the requirement of storing the VM's virtual disk files on an expensive storage device that is shared between the Hyper-V hosts. For example, you can migrate VMs between two standalone Hyper-V hosts that contain only built-in, direct attached storage. This dramatically lowers the cost barrier to implementing virtualization. If you add another new capability, that of hosting Hyper-V virtual disks on SMB file server shares, a whole new range of virtualization infrastructure possibilities open up. Add the easy-to-implement disaster recovery capabilities of Hyper-V Replica, and production-worthy virtualization is now available, at low cost, to companies of all sizes.

Once a nagging constraint, the scalability limits reached by Windows Server 2012 Hyper-V (and thus Hyper-V Server 2012) are such that I think no one simply ever needs to think about them again. Since Mike's article describing the Developer Preview, Microsoft has doubled many of the product's limits on top of the original 2 to 8 times improvement over R2's Hyper-V (Figure 1)! Jeff said at the time, "We can believe this product scales much higher – we just haven't had the time to test the upper limits."

All of these features are available in the free Hyper-V Server 2012.

Microsoft positions Hyper-V Server, regardless of version, mostly for use cases involving licensing. One scenario involves running Linux or other non-Windows VMs on Windows Server hosts. These VMs don’t require Windows OSE licenses, so why pay for a copy of Windows Server Enterprise or Datacenter editions and their associated licenses when you can host them on Hyper-V Server? A second scenario is for the VDI (virtual desktop infrastructure) scenario. In this scenario, the VMs on the Hyper-V host are running a Windows client, not a Windows Server, so the OSE licenses included with Windows Server Hyper-V are wasted. A similar scenario is of hosting Windows OSes earlier than Windows Server 2008, such as 2003 or 2003 R2.

The last use case is for the “little to no IT” small business scenario. In this case, a Hyper-V host is situated at a small business where some employees are somewhat technical, but not up to the task of virtualization host server management. The bottom line is that you don’t want them to logon to the parent partition and inadvertently do anything to harm the host. With a simple command line interface, there’s nothing to tweak or otherwise poke around with.

How does Hyper-V Server 2012 compare to VMware's free version of ESXi 5.0, its vSphere Hypervisor 5? vSphere Hypervisor is limited to 4 vCPUs per VM, while Hyper-V Server supports up to 64. Host RAM is limited to 32 GB, while Hyper-V Server supports up to 4 TB. vSphere Hypervisor 5 also contains no VM migration (vMotion), storage migration (Storage vMotion), high availability, extensible switch or VM replication features. It can only be managed by connecting directly to the host with the vSphere client, whereas Hyper-V Server supports both Hyper-V Manager and System Center Virtual Machine Manager remote management.

Microsoft's Hyper-V Server 2012 (registration link at http://microsoft.com/hvs) really deserves appreciation from a wider audience. It takes the amazing array of enhancements to Microsoft's virtualization solution –and gives them to you for free.