Virtualization, in some cases, can create more problems than it solves. It helps IT create a fluid environment where virtual servers can be turned on or off with a few mouse clicks. This is powerful, but dangerous if you don't know the impact of each change beforehand.

From a planning and execution perspective, virtualizing a small set of servers can be a relatively easy process. Those implementing a small scale solution are usually familiar with all of the physical devices, workload and configuration details and other key considerations involved. However, bringing virtualization to an enterprise environment is a different story entirely. Large scale virtualization projects necessitate a data-driven approach, carefully evaluating elements, such as asset identification, business considerations, technical constraints, and workload patterns.

Most virtualization initiatives are approached as tactical exercises in making sure the technology works at a base level. The focus becomes "do these assets fit together on this server?" without consideration of "should they reside on the same server?" When virtualization is rolled out on a large scale, it needs to be part of an overall consolidation strategy in the data center that is supported by sufficient analysis and planning. Testing in the lab is not enough. This only evaluates technical issues without taking into consideration important business factors that the company will face when they move into the production environment.

Planning for virtualization is more than a sizing exercise. Virtualization analysis and planning should include:

Managing Inventory: The "one box per application" mentality-along with continuous hardware upgrades with greater computing power-has driven a proliferation of diverse servers that are increasingly underutilized. Most organizations don't have a strong enough discipline around purchasing or asset management, making it difficult to inventory servers. Once organizations move into the virtual world-where you can create a logical machine without having any paper trail-this problem grows exponentially. Organizations will be caught in the same trap as they currently are with physical servers: not knowing which servers exist, who created them, which applications they support and whether or not they need them. This has a direct impact on licensing costs and ongoing management issues, which threaten the cost savings of virtualization. Because of this, organizations need to put technologies and processes in place for tracking and managing the rules around the implementation of virtual servers.