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Tip 8 - Harvest OS Licenses by Virtualizing Everything

by Greg Shields

In the verbal war between the major hypervisor players today, there's one fact that's missing out of many of the ROI calculations: Namely, that Microsoft's licensing verbiage hands a very special benefit to organizations that virtualize. Written in plain English on Microsoft's Web site ( http://www.microsoft.com/licensing/about-licensing/virtualization.aspx ), the “new rules” when it comes to OS licenses are:

Windows Server 2008 Enterprise. Run up to four software instances at a time in virtual operating system environments on a server under a single server license.

Windows Server 2008 Datacenter. Run any number of software instances in physical and virtual operating system environments on a server.

These license terms, which were made available with the original release of Windows Server 2008, translate to a direct cost savings to businesses that virtualize their IT environments. In short, every time you virtualize a copy of Windows Server 2008 (or R2) Enterprise Edition, you gain either four or unlimited additional free licenses of the OS.

This is worth saying again: Virtualize one server, gain free licenses . For this reason alone, it makes sense for every environment to consider moving each and every server in their environment to run atop a hypervisor.

For Consolidation, Consider 1:1

“Virtualize everything? But not all my servers make good candidates!” That's an excellent point, and it follows the guidance that pundits have been suggesting for years; namely, that every environment should go through a virtualization assessment first to determine which physical servers will make good virtual servers.

However, there's an important point that's missing out of all the first-generation virtual assessment guidance. Most assessment tools (VMware's Consolidation, Hyper-V's MAP tool, Vizioncore's vConverter, Veeam's Monitor, and others) assume that your primary goal is to compress as many virtual servers onto physical hosts as possible. Their ROI calculations show that if you can net, for example, 10 virtual servers per physical server, you'll see a better return than if your consolidation ratio is 6:1.

The problem with this approach is that it's exceptionally short-sighted, assuming that consolidation is the only goal with virtualization. Admittedly, the historical approach to virtualization's value proposition related to reducing data center footprints, power, cooling, and all the other artifacts of a distributed architecture. But today's conventional wisdom is expanding those initial expectations to a much wider audience. Namely, that the benefits of virtualizing are worth more than the cost of virtualizing, particularly so when your hypervisor doesn't cost you much (or anything) to implement.

Consider the situation where you've virtualized every server in your infrastructure. Some of those servers don't need a lot of resources to accomplish their mission. These, you can consolidate onto a small number of hosts to share their physical resources. You might see there a 6, or 10, or 20 virtual server per physical server consolidation ratio with these low-utilization servers. With these servers, managing their performance to gain the best consolidation ratio assures you the best return.

Others need all the resources you hand to them. With the “old” conventional wisdom, you might have elected to leave these as physical servers. Using the “new” conventional wisdom and a no-cost hypervisor, virtualizing these servers with the goal of only one virtual server per physical server nets you no added cost but many more licenses.

Further, by virtualizing that server, you now gain all the benefits of virtualization: whole server backups and immediate restore, accident protection with snapshot technology, failover capability to new hosts to protect against hardware failure, and portability of that server in the case of a disaster. For a few percentage points of performance loss (associated with the hypervisor's overhead), you stand to gain substantial improvements to your operational flexibility.

Greg Shields is an independent author, instructor, and IT consultant based in Denver, Colorado, and a co-founder of Concentrated Technology. With nearly 15 years of experience in information technology, Greg has developed extensive experience in systems administration, engineering, and architecture specializing in Microsoft systems management, remote application, and virtualization technologies. Greg is a Contributing Editor and Columnist for TechNet Magazine, and is the author of five books, including Windows Server 2008: What’s New / What’s Changed. Greg is also a highly sought-after instructor and speaker, speaking regularly at conferences like TechMentor Events, and producing computer-based training curriculum for CBT Nuggets.  Greg is a recipient of Microsoft "Most Valuable Professional" award with a specialization in Windows Terminal Services.