New research finds that 25% of all physical servers -- and 30% of all virtual servers -- are comatose. These are systems that have no activity in the last six months.
The problem with comatose, or zombie, physical servers is well known. Past studies have routinely put the number of undead enterprise physical servers in the 20% to 30% range. But this latest research looked at virtual servers as well, and they may represent a significant cost to IT departments.
That's because users may be paying licensing fees on their virtual servers, as well as on the software they support, said the researchers.
Comatose servers, both virtual and physical, may also represent "an unappreciated security risk" because they aren't patched and maintained, according to the research paper by Jonathan Koomey, a research fellow at Stanford University, and Jon Taylor, a partner at the Anthesis Group, a consulting firm.
Koomey and Taylor looked at 16,000 servers in about 10 data centers using data collected by TSO Logic, an energy efficiency software vendor. This study is an update of the earlier one, which found that 30% of all physical servers were comatose. The decrease to 25% in these results may be a result of the larger sample size.
The cost of running comatose systems varies depending on age and whether it has been fully depreciated or whether all the invested value in the physical server has been realized, said Taylor in an interview. "The easiest argument to make is the waste in energy it's consuming," said he said.
With regard to virtual servers, "it was shocking how equally large it was," he said, noting the costs for virtual server licensing and licenses for any software still running on the server. "I think they are draining a lot of operational cost."
The problem may be one of motivation: IT managers aren't necessarily measured on well they control costs.
"The most important measure of an IT shop is typically availability," said Leon Kappelman, a professor of information systems at the College of Business at the University of North Texas.
Kappelman, who had no involvement with the study, said it's important to understand the context behind why a server is idle. He knows of users who keep servers sitting for months because they are used for backup, especially when needed to meet seasonable demands.
"They are addressing a real problem," said Kappelman, of the study. "There is waste in IT and there has always have been."