Joe Latrell, IT manager and lead programmer for GetMyHomesValue.com, a real estate data services company in Lancaster, Pa., knows that it's all too easy for even a knowledgeable and experienced IT veteran to make mistakes while managing a complex server-consolidation project. "You have to think about everything," he says. "It can be a minefield."

Server virtualisation projects are usually easy to justify on both financial and operational grounds, but that doesn't make them foolproof to execute. Pitfalls, such as inadequate planning, faulty assumptions or failure to quickly detect post-deployment glitches, can entrap consolidation project leaders and team members at almost every stage.

"Every time [we] felt that we covered every base, that every single thing had been looked at ... that's when the danger started," says Latrell, whose project experienced a variety of woes, including underpowered servers, configuration snafus and budget constraints.

Avoiding disaster while keeping a complicated consolidation project on schedule and within budget isn't easy. In fact, Latrell believes that making at least a few mistakes along the way is inevitable. "It will go wrong: Be prepared," he warns. "On the other hand, planning and learning from others will keep you from making the big and obvious mistakes."

Plan for success

While even the most thorough, painstaking planning can't completely eliminate project mistakes, building a detailed virtualisation design and deployment strategy will help minimise the number of gotchas. "Planning is really key for server consolidation," says Justin Gallagher, senior IT consultant at KDSA Consulting LLC in North Andover, Mass.

Thorough planning creates a road map that helps managers gather the knowledge required to avoid most major problems. "I think people aren't spending enough time thinking about the issues of the existing workloads and how you migrate those into a virtual environment, and what does that mean in terms of , cost structure, ongoing expense and high availability," says Jeff Nessen, IT consolidation practice manager at Logicalis, a systems integrator in Bloomfield Hills, Mich.

Gallagher says that consolidation planning also needs to address an organisation's future needs. "Look at what you're going to do a year, three years and five years from now," he suggests. Gallagher notes that servers, software and other system elements need to be planned with an eye toward anticipated growth. "You don't want to get yourself in a situation where you do this whole big upgrade and then you find you need more [server capacity] later on."

Jason Cooper, a consultant at C/D/H Technology Consultants in Grand Rapids, Mich., agrees that every consolidation plan needs to address scalability. "From the standpoint of server virtualisation, it's very important to have a system that scales and meets the performance need of the load you're putting on it," he says. "We often run into issues with organisations that either didn't allocate enough storage, or simply didn't correctly anticipate the amount of server power that was going to be needed to facilitate their server consolidation project."

It's extremely common to overestimate the physical-to-virtual consolidation ratio, experts say.

Planning is particularly critical when managing a data centre with outmoded equipment and a limited budget. The moment he arrived on the job, Latrell inherited a motley collection of servers, including converted desktop PCs and a mix of underpowered stand-alone and rack-mounted machines. He was determined, however, to streamline the collection into a uniform line of rack-mounted servers and, in the process, to winnow down the total number of units from 23 to 12.

"We understood we didn't have the budget to just go out and buy 12 new servers, so we decided to purchase the machines as we could afford them," he says. "We planned in advance to implement one piece at a time, and it's worked out well."