(This is the third article in a five-part series.)

Virtualization is so popular these days, there’s a good chance you’re already doing it. Server virtualization, which allows multiple logical servers to share a single physical server, is especially widespread. Virtualizing servers is far more efficient than simply purchasing new server hardware for each new application you deploy, a strategy that can quickly result in server sprawl. By reducing the amount of hardware in your data center, aggressive virtualization can also yield a sharp reduction in energy consumption. For example, virtualization helped Bryant University, in Smithfield, R.I., reduce its server count by 47 percent, yielding energy savings of approximately 15 percent, according to Rich Siedzik, the school’s director of computer and telecommunications services. Popular makers of server virtualization tools include VMware Inc., Citrix Systems Inc., and Microsoft Corp.

Two other forms of virtualization can contribute further energy savings:

• Desktop virtualization, also known as thin-client computing, allows users to run PC applications or an entire desktop remotely over a local area network, wide area network, or the Internet. Thin-client devices are essentially stripped-down computers that rely on central servers for most of their software and processing power. A typical thin client consumes up to 80 percent less energy than a typical PC, according to data from Hewlett-Packard, which sells both types of hardware.
• Storage virtualization, in which multiple physical storage repositories behave like a single physical storage pool, can improve disk utilization, reducing wasted storage space that consumes power unnecessarily.

Stan Gibson is a Boston-area technology writer.

Other articles in this series:

Getting started on green IT, part one: Update your hardware

Getting started on green IT, part two: If it’s not in use, turn it off

Getting started on green IT, part four: Straighten out your storage

Getting started on green IT, part five: Consolidate data centers