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Closing the VM sprawl floodgates

VM sprawl is the result of irresponsible server provisioning, so you need to implement stringent resource-allocation policies.

You were poised for greatness. You did your homework and developed a plan to save tons of money by virtualizing 40 servers.

But a few months later, you have only 20 of those servers virtualized, and you are out of resources. Even worse, you didn't even come close to the projected savings. Where did your resources go? What happened to the cost savings you had so carefully laid out?

VM sprawl happened.

The shift to virtualization marked a dramatic change, seriously reducing both the complexity and effort involved in procuring new server resources. Before virtualization, buying a server was like buying a large household appliance in a warehouse somewhere. It cost a lot, and you had to pay extra for delivery and installation. A virtual server, on the other hand, is like a pack of gum: inexpensive and convenient to buy.

As a result, server resources have become an afterthought in many projects. People request new virtual servers at the last minute, just like a pack of gum. And some even grab a second pack, just in case they need it later.

As virtualization streamlined the server acquisition process, it opened the floodgates. People began to unload years' worth of pent-up server requests, causing virtual infrastructures to grow beyond their original designs -- a phenomenon known as virtual machine sprawl, or VM sprawl.

What is VM sprawl?
At first you rarely even notice VM sprawl. It is not until you have run out of resources that you are confronted by this reality. With the financial and operational hurdles removed from server acquisition, people have become irresponsible in both practice and policy.

It is great when you can make your co-workers see the value of virtualization, but they must also become responsible consumers of this technology. Otherwise, you'll continually be fighting to control VM sprawl. To get your original virtualization project back on track and to stabilize your infrastructure, you must restore sanity. Put practices into place that encourage a thoughtful and well-planned allocation of resources.

You must reserve resources for active projects, or at least develop a schedule to replenish those resources when they are needed. You must understand the effects of creating each VM and become and expert at resource forecasting. Ask yourself, "What will the allocation of X amount of resource Y do to my active project plans?"

When you retake control of your resource consumption, your virtual infrastructure will become the valuable asset you originally envisioned. And once again, you will find yourself poised for greatness.

About the expert
Mark Vaughn (MBA, VCP, vExpert, BEA-CA) is a consulting principal for data center virtualization with INX, a Houston-based solutions provider. Vaughn has more than 14 years of experience in IT as a Unix administrator, developer, Web hosting administrator, IT manager and enterprise architect. For several years he has focused on using the benefits of virtualization to consolidate data centers, reduce total cost of ownership, and implement policies for high availability and disaster recovery. Vaughn is a recipient of the vExpert award for both 2009 and 2010, and he has delivered several presentations at VMworld and BEAWorld conferences in the U.S. and Europe. Read his blog at

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