In research Gartner estimates that more than 80 percent of enterprises now have a virtualisation programme or project in place, but that only 25 percent of all server workloads will be in a virtual machine (VM) by the end of 2010.
Gartner said many IT leaders believe they have virtualised their x86 servers, but that they have to plan for two to three times the growth of virtualization in their IT portfolio to deal with the challenge.
"Virtualization will continue as the highest-impact issue challenging infrastructure and operations through to 2015, changing how you manage, how and what you buy, how you deploy, how you plan and how you charge," said Gartner analyst Philip Dawson.
Dawson added: "virtualization now drives efficient IT from all angles, including data centre design, platform updates, and application and infrastructure modernisation, as well as traditional and new delivery models, such as infrastructure utility and cloud computing. But virtualization does take investment and the savings are not a given."
Gartner says virtualised licensing continues to be a "major stumbling block" to widespread adoption of virtualization.
As vendors change their software pricing and associated license provisions to accommodate virtual use, IT departments must plan to spend an increased amount of time per contract to understand the effect of such changes on planned software use, said the analyst. Those that don't are likely to experience significantly increased costs and the "unintended impairment of their current license rights", said Gartner.
Virtualization software providers, including Microsoft and Citrix, have been criticised for causing confusion in the marketplace with their virtualization licencing models. IT departments and resellers have claimed, that in some instances, even the providers don't know the actual cost of their virtualization offerings to the end user.
This story, "Gartner: Server Virtualization a Challenge" was originally published by Computerworld UK.