But as virtual machine technology moves out of development labs and into production server environments in large numbers, some administrators are finding that the growth of virtual servers is getting ahead of the tools available to effectively manage them.

Existing server-monitoring tools are increasingly aware of virtual servers, but most aren't yet sophisticated enough to interpret feedback in a virtual machine context -- much less act on it. "They don't take into account the particulars of virtual machines," says Frank Gillett, an analyst at Forrester Research Inc.

For example, a virtual machine may be running at 100 percent utilization but using only a fraction of the underlying server's resources. "Some of the things you monitor no longer mean the same thing," Kuzmack says.

"It would be nice if all of our standard tools worked in the virtual space, but they don't, and it doesn't look like they're going to anytime soon," says Norm Fjeldheim, CIO at Qualcomm Inc. in San Diego. He is evaluating tools targeted at virtual machine management to fill the gap.

For many organizations, identifying the root cause of virtual server problems and rectifying them remains largely a manual process. As the number of virtual machines in the data center increases, solving those problems in an automated way becomes more urgent.