Even as enterprise IT managers roll out more virtual servers, they remain hesitant to put their most important and sensitive applications on them, a Forrester Research survey finds.

According to the survey of 60 enterprise server infrastructure executives and managers, 70% plan to consolidate e-mail servers, but just 20% intend to use virtualization to augment that effort. The same goes with applications that support security functions. Less than half of the 55% planning to consolidate e-commerce applications expect to use virtualization.

"Because of high use, e-mail is far more likely to be consolidated onto larger dedicated servers than onto slices of a server -- of any size," a March Forrester report reads. E-commerce applications, the research firm says are another unlikely candidate for virtualization as the business depends too much on successful transaction rates. "Clearly it's a bad thing if the electronic cash register rings less often because it can't get the server resources it needs when it needs them," the report reads.

Security functions are also less likely to land on virtual servers. Close to 70% intend to consolidate security functions, yet just 28% will use virtualization in those plans. Virtualizing firewalls, VPNs, spam filters and other security-related tasks didn't rate high with survey respondents. According to Forrester, "These applications don't consume full servers, but their importance to the business makes them less likely to be deployed on a maturing technology."

As for those applications most likely to find a spot on virtual servers, Web and file servers topped the list with each garnering 40% of survey respondents' votes. Enterprise applications such as CRM and ERP also ranked high. Print servers and systems management applications also seem likely to reside on virtual servers, with 38% of respondents saying each is likely to be consolidated via virtualization.

"File servers have been a logical target for virtualization ever since it emerged. Web and back-office applications can hog resources when driving the business and although typically underutilized, small departmental versions tend to spring up everywhere," Forrester explains. "Dedicating physical servers to perennially low utilization functions such as print serving and systems management is wasteful: They're good targets for virtualization."