Data center managers who championed virtualization and green computing in 2007 now face the task of delivering the benefits they promised -- something industry watchers say will be no small feat.

As projects move beyond the planning phase in 2008 into broader deployment, data centers managers will need to evaluate how they're going to manage and support the new technologies without overhauling their entire infrastructure.

"Virtualization and green computing will flip-flop for a while, because they represent challenges beyond what they are said to do," says Robert Whiteley, senior analyst at Forrester Research. "We will see a bit of a virtualization hangover at first because while a lot of people have embraced the technology and seen some success on x86 servers, virtualization forces IT to look differently at managing an environment. And the greening of IT, that is going to be a challenge because a lot of companies don't have a full grasp on what it is yet."

Managing more than VMware

To start, virtual server management technology will become more critical as VMware faces competition in the hypervisor market that until now included few players.

With Citrix (considering its XenSource buy), Microsoft, Oracle and Sun all having plans for virtualization, data center managers will for the first time "face islands of hypervisors within their IT shops," which will have to be managed as a cohesive whole to truly cash in on the benefits of the technology, says James Staten, principal analyst at Forrester Research. Hypervisor providers and management vendors alike will be working to deliver the platform on which multivendor virtual servers can be managed. For instance, VMware acquired virtual server management software maker Dunes Technologies earlier this year. 

"The market is going to see the need for a heterogeneous virtualization management platform that we haven't seen up until this point," Staten says. "It will cause a significant shake-up in the management space when start-ups pop up, and bigger players that haven't been doing a very good job will look to acquire them."

In addition, data center managers are considering virtualizing not only server resources, but also storage, network, desktop and application resources -- -- which will drive a need for more comprehensive management tools. But data center managers aren't about to replace their existing management tools, so industry watchers say vendors will have to work to cover more platforms and develop standards to help customers manage heterogeneous environments.