Moving into server virtualization is little like playing a video game: The first few rounds are easy, but as many companies advance in deployment, they are increasingly seeking more specialized help.

Consider this data point: Technology job board Dice has some 1,500 job listings for people with VMware experience alone. A year ago, there were just a few hundred.

Tom Silver, senior vice president of marketing and customer support at Dice Holdings in New York, said virtualization is one of the fastest growing areas he has seen on the job board, and "it's just beginning to take off." He said he wouldn't be surprised if the number of VMware-specific job postings rises by 30 per cent or 40 per cent in a year.

Virtualization found its way into data centers thanks to the effort of system administrators willing to learn about it and pilot it. "If VMware had made that difficult to do, they would not have been successful," said Robert Whiteley, an analyst at Forrester Research.

But once virtualization is deployed beyond 10 per cent to 15 per cent of a company's production servers, the demands it places on networking and storage grow as well, Whiteley said. Virtualization is also being used in more sophisticated ways, such as in disaster recovery. These uses require more monitoring, attention and planning. And if desktop virtualization takes off in the way that vendors expect, demand for virtualization expertise will only increase, he said.

Some of the virtualization jobs advertised on Dice and other jobs boards are seeking "three to five years" of experience for a technology that was relatively rare five years ago. Many job listings cite VMware skills as one of a long list of skills needed for a system and server administration post, but there are also job postings specific to the technology, where technical specialists, administrators and architects are sought. For those ads that list pay, salaries as high as six figures for senior-level experience can be found.

Virtualization is also being used in more sophisticated ways, such as in disaster recovery, Whiteley said. But if there is a skills shortage, it's not slowing down the deployment, he said.

At the Forrester IT conference here, some users involved in virtualization said they were relying on outsourcers to handle any skill needs or turning to contractors, as well training internally.

"Anytime you add a layer, even though it has its benefits, you got another layer to manage," said Reese Coombe, an internal technology managing consultant at a company he didn't want identified. While there will be gains from the technology, such as speedier application deployments, he said specialized expertise will be needed.