Imagine an employee who spends 90 percent of the workday wandering the halls and taking catnaps. In most organizations, that person would be sent packing before closing time on Friday. But not so in data centers. Governments all over the world keep them packed with servers that are kind of like this hypothetical slacker - they don't live up to their potential.

"Average CPU utilization is probably somewhere in the range of 5 percent to 7 percent, maybe 10 percent to 12 percent on a server that's really being taxed," said Tennessee CIO Mark Bengel.

Just as each person in an office - productive or not - commands a desk and chair, a paycheck and benefits, each server box in a data center takes up floor space, arrives with an initial price tag, and generates ongoing costs for software licensing, power, cooling and maintenance. These costs accrue whether the box performs at 5 percent of capacity, or 75 percent.

The desire to get a much bigger return on hardware investments is one reason some government organizations turn to virtualization technology. Virtualization uses software to simulate multiple entities inside one physical server box. Each entity has its own personality and performs as though it is a real component.

Virtualization can mean, for example, creating 20 independent servers in one physical box, each with its own operating system and configuration, and the ability to run a separate application. It might mean creating a dozen desktop PCs from one server and 12 thin clients, or dividing the resources of one network infrastructure into what looks like three entirely separate networks.

Much interest in virtualization focuses on servers. One important reason data center managers create virtual servers is to consolidate facilities, running more applications on fewer physical boxes.

That strategy offers several benefits, said Gary Chen, senior analyst with the Yankee Group. "No. 1, you'll save money on hardware: You won't have to buy as many servers. No. 2, you'll save money on space." Most government agencies and private companies pay for data centers based on square footage, he said.

"No. 3, you'll also save on power," Chen added. That's good for the environment as well as for the financial ledger, he said.

Virtual servers also make it easy to troubleshoot hardware and plan for disaster recovery. Because virtual servers are simply software, if the box they're running on experiences hiccups or crashes altogether, it's easy to slide them onto another piece of hardware, leaving end-users none the wiser, Bengel said.

 
Spin it up
The server farm in Tennessee's state government data center hosts 350 virtual machines. If a physical server breaks down entirely, the storage area network (SAN) that houses the virtual servers can send them to a different box, Bengel said. "It gives you tremendous flexibility to perform maintenance in the middle of the day, which you normally couldn't ever do." And if a disaster hits the data center, the SAN can send any virtual server to a backup location. "I can just spin it up at another farm at another site, and everything is intact, including the IP address."  

Virtual servers work well for testing updates, code changes and patches, said Rob Campbell, senior technology specialist with the Microsoft Federal Team. They also reduce the amount of hardware a person needs to lug around when demonstrating applications, he said. "If I want to set up a demo environment that has multiple servers and clients interacting, I can do all of that on top of one laptop, because each of the demo machines can run in a virtual environment," Campbell said.

A virtual server also is an ideal platform for software developers who need a machine for a few months, said Max Arnold, Tennessee's executive director of data center operations. "Once they have [