IBM has seen this trend writ large. About 60 to 70 percent of the data centers it currently builds are modular in design, says IBM's Sams.
3. Cooling is key
Five years ago, customers were installing 500 watts of servers on each rack; now, a rack of servers frequently consumers 20,000 watts, says IBM's Sams. With greater energy consumption, of course, comes greater heat, which makes cooling technologies that much more important.
The size of the data center is a key factor in determining which cooling option would be best. "What worked for large data centers did not necessarily work well for small data centers," Sams says.
In small data centers, putting the cooling devices as close as possible to the server racks mattered most. In larger data centers, traditionally raised flooring and perimeter chillers are most efficient, he says.
When looking at cooling options, technology makes a big cost difference. The operational costs of the worst cooling systems were two-and-a-half times worse than the best systems, Sams says.
4. Virtualized everything
Virtualization has a lot of benefits for corporate IT, from greater flexibility to more efficient use of resources. Servers are not the only component in the data center that can be virtualized, of course.
For YouSendIt, virtualizing its storage was the next step for the company on its growth path. Many companies will try to do their own storage infrastructure and then outsource it. Finally, those companies -- like YouSendIt -- for whom storage is a large part of their business, will often bring storage back inside and use a virtual infrastructure to run storage clusters most efficiently.
"The ability to tune and monitor and scale is much greater," Chevsky says.
The company's data center consists of racks of blade servers that satisfy different tiers of customers: some are dedicated, others are virtualized.
"We have quite a few different clusters ... that do different levels of processing," Chevsky says.
5. Self-diagnosing data centers
Due to needs around virtualization, real-time heat monitoring, and redundancy, IT managers are increasingly looking for data centers with more smarts. A key question that IBM asks its clients is how smart do they want their data center to be. Common requests are for real-time monitoring of heat and server and disk events that could signal an impending failure.
The intelligence built into a data center will be the aspect of design that will likely change the most over time, says IBM's Sams.
"The whole marketplace is on a really steep innovation curve right now," he says. "We expect a lot of interesting things to happen in the next three to five years."