IT managers are reluctant to put their most important and sensitive applications on virtual servers, despite the technology's growing popularity.

That's the finding of a new survey by Forrester Research, called "What applications are enterprises virtualizing: And what will you virtualize next?"

Forrester discovered that IT managers were happy to put less vital applications on virtual servers – such as web and file server systems, or CRM (customer relationship management) and ERP (enterprise resource planning) applications. However, they baulked at virtualising email, e-commerce, security and other mission-critical applications.

According to the Forrester survey, which questioned 60 enterprise server infrastructure executives and managers, 70 percent planned to consolidate email servers, but just 20 percent intended to use virtualisation to augment that effort.

The same was true for applications supporting security functions. And less than half of those planning to consolidate e-commerce applications expected to use virtualisation.

"Because of high use, email is far more likely to be consolidated onto larger dedicated servers than onto slices of a server – of any size," the report stated.

E-commerce applications, the research firm said, were another unlikely candidate for virtualisation, 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."

Nearly 70 percent of respondents intended to consolidate security functions, but similarly just 28 percent included virtualisation in those plans.

Virtualising firewalls, VPNs, spam filters and other security-related tasks didn't rate highly, either. 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."

On the other hand, more than 40 percent were happy to virtualise web and file server applications. Enterprise applications such as CRM and ERP also ranked high, as did print servers and systems management applications. Thirty-eight percent of respondents were considering virtualisation of the latter.

"File servers have been a logical target for virtualisation ever since it emerged," Forrester explained. "Web and back-office applications can hog resources when driving the business and although typically under-utilised, small departmental versions tend to spring up everywhere.

"Dedicating physical servers to perennially low utilisation functions such as print serving and systems management is wasteful: They're good targets for virtualisation."