With VMware's success, virtualization has taken on a life of its own. Beyond the server, vendors are now touting products for virtualizing any and every layer of the infrastructure: network, storage, desktop, application, database, user interface - even security and mobility.

This technology explosion makes sense. Although enterprises gain incremental benefits from applying virtualization in one area, they gain much more by using it across every tier of the IT infrastructure.

Virtualization and you Before you decide how much virtualization is right for your enterprise . . .
ASK YOURSELF
•	Does my security infrastructure rely on IP addresses and how will that impact my virtualization plans?
•	What processes do I use to troubleshoot root causes and how can I modify that to support virtualization?
ASK YOUR VENDORS
•	What kinds of ties does the product require to the physical devices and how do you ensure such ties will not interfere with the product’s flexibility?
•	How well does it integrate with other types of virtualization (say, server, storage, network and desktop)?
•	What management tools support the product and how do such tools manage underlying physical devices?
•	Is it possible to manage the product via a single console that provides an overview of the whole environment?
•	Does your virtualization technique follow accepted standards or will your virtualization lock me into you as a sole vendor? (Users can use both VMware and Microsoft Virtual Server within one environment, as both support importing virtual machines from one to the other. But that’s about as far as interoperability currently extends.)

"It's very difficult to apply virtualization to one part of your infrastructure unless you apply it to many or most parts of your infrastructure," says Andreas Antonopolous, senior vice president of Nemertes Research. "If you decouple some of your resources from the physical, yet they interact with other resources that are coupled to the physical, it lessens the benefits you achieve."

Antonopolous offers the example of implementing server virtualization without network or storage virtualization. "Some of the biggest benefits you get from server virtualization, like the ability to boot a given server in a different data center for disaster-recovery purposes, you can only do if your storage is virtualized and you have a [storage-area network] replicated between the two sites. Once you have those pieces in place, the benefits from server virtualization become huge."

The problem is that not all virtualization technologies are equally mature. Whereas server virtualization seems to have hit its stride, other areas are not as far along, especially in the management and security realms. And getting the various virtualized pieces to work together cohesively can be a big challenge.