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Rearranging the data center
Another option is to rearrange the data center for better cooling efficiency. Bloomsburg Hospital is an open-systems shop that just built a new data center that will eventually house 70 servers, each with as many as six direct-attached disk drives. Robert Theiss, chief information officer at the Bloomsburg, PA, organization, planned the new data center with energy and cooling in mind. "We were worried about putting in a greater [energy] load," he says.
The hospital turned to American Power Conversion (APC) Corp., West Kingston, RI, to engineer a new power and cooling system. "Right now, we're running at about 40% of our maximum power," says Theiss, which leaves room for expansion. For maximum cooling, Theiss spread the servers and storage over racks set up in two rows separated by three aisles. AC units push cool air over the front of each row to cool the entire system.
The cooling rule of thumb for raised-floor data centers has jumped from 4kW to 6kW per rack. "Beyond 6kW, you can't cool with just a raised floor. Today, a lot of gear is running over 4kW per rack, which is getting close to the threshold," says Gartner's Bell.
In response, large organizations are creating hot and cool aisles, and using blanking panels within racks to assist with air flow. Cool air is pushed into the bottom of the rack from the cool aisle and exits as hot air from the top of the rack into the hot aisle (see
"Data center design and air flow," below).
This was first published in March 2007