Large businesses are beginning to use software that lets them consolidate applications and operating systems onto as few Intel-based servers as possible, easing administration and lowering costs.

Known as server virtualization, the technology promises to let customers divide the server and create independent environments that can run different applications and operating systems on the partitions or processors of the Intel server. Companies, such as Connectix, SW-Soft and VMware are providing the software that lets Intel servers emulate the software partitioning and virtual machine capabilities of bigger Unix servers from Hewlett-Packard, IBM and Sun, and mainframes from IBM.

There are two types of server virtualization techniques in Intel machines - virtual machine and virtual server. In a virtual machine environment, multiple operating systems run side by side on the individual processors or partitions of the server. In virtual server environments, one operating system is virtualized across the partitions and processors, where it can run multiple applications. With virtualization software, a customer could run an e-mail application on the Windows partition while running a Web server under Linux, or run several lightweight applications such as calendaring or mail on a Linux virtual server environment. Without server virtualization software, it would be necessary to add servers as the number of applications grew.

The desire to consolidate servers is growing, too. IDC predicts that 75% of large corporations will consolidate portions of their servers or storage this year. The research firm says the Windows NT/2000 market will see more than $1.3 billion spent on consolidation; Linux consolidation will top $232 million. By 2006, consolidation in the Windows NT/2000 market will more than double to $2.7 billion.

"We are trying to reduce the number of overall servers we use," says Randy Robinson, vice president of IT for Unum Provident, the world's largest disability insurance provider, in Chattanooga, Tenn. The company's server farm has grown by 50% over the past two years.

"If we have a team that wants to develop an application, typically we will need new servers for development, testing and training," he says. "With virtualization, we can take a two- or four-processor server and create multiple instances of the operating system, which allows us to segment and partition our development, training and testing activities, without having a negative impact on someone else."