There is no single answer that meets the needs of every data centre operator.
When Elbert Shaw, a project manager at Science Applications International Corp. in San Diego, consolidated U.S. Army IT operations in Europe for several dozen locations into four data centres, he had to come up with a unique solution for each location. At a new facility, he was able to put in 48-inch floors and run the power and cooling underneath. But one data centre being renovated only had room for a 12-inch floor and two feet of space above the ceiling. So instead of bundling the cables, which could have eaten up eight of those 12 inches, blocking most of the airflow, he got permission to unbundle and flatten out the cables. In other instances he used two-inch underfloor channels, rather than the typical four-inch variety, and turned to overhead cabling at one location.
“Little tricks that are OK in the 48-inch floor cause problems with the 12-inch floor when you renovate a site,” says Shaw.
“These facilities are unique, and each has its own little quirks,” Koomey says.
Power management tips
Various experts suggest the following ways of getting all you can from your existing power setup:
— Don’t oversize. Adopt a modular strategy for power and cooling that grows with your needs instead of buying a monolithic system that will meet your needs years down the road.
— Plan for expansion. Although you don’t want to buy the extra equipment yet, install conduits that are large enough to accommodate additional cables to meet future power needs.
— Look at each component. Power-efficient CPUs, power supplies and fans reduce the amount electricity used by a server. But be sure to look at their impact on other components. For example, quad-core chips use less power than four single chips but may require additional memory.
— Widen racks. Use wider racks and run the cables to the side, rather than down the back where they block the air flow. Air flows from the front of a server, through the box and out the back. There are no inlet and outlet vents on the sides. It is similar to a PC, and you can put a piece of plywood along the side of server without affecting airflow through the machine. But, if you put the wood along the back, it will overheat.
— Install a UPS bypass. This is a power cable that goes around the UPS rather than through it. That way, if the UPS is taken offline, there’s still a route available for the electricity to flow through and you have power redundancy when you bring a UPS device down for maintenance.