Framingham, Mass.-based IDC expects the number of servers in the U.S. to grow from 2.8 million in 2005 to 4.9 million by 2009. Data centers "are becoming more and more swollen," causing IT costs to rise quickly, IDC analyst Vernon Turner said at the IDC Virtualization Forum, which was in New York last week.

The constant need for more horsepower, and the accompanying expense, are leading some IT operations to slowly turn to virtualization technology.

The IT staff at Deluxe Laboratories, a Los Angeles-based media services subsidiary of Rank Group PLC, manages about 400 mostly x86-based servers, and the count is growing by about 30 percent per year, said Mark Winter, executive vice president for IT.

The company is testing virtualization technology installed by St. Louis-based consulting firm Savvis Inc., but Winters estimated that it will take three years to expand its use throughout the firm.

"I'm getting to the point where I'm having difficulty managing," said Winter. The server growth has pushed the company's ratio of servers to systems administrators to about 30-to-1, far higher than Winter would like. "Right now," he said, "I'm at half the number [of administrators] I need."