WITH THE COST of electricity soaring by 30% to 60% this year, IT managers are looking for ways to put some proverbial air in their storage systems' tires to eke out a few extra miles per gallon from their storage SUVs.

EMC, for example, has seen a surge in interest for 500GB disk drives in its Symmetrix DMX platforms, says Bob Wambach, director of EMC Symmetrix product marketing. The reason? A 500GB drive offers 66% more capacity than a 300GB version, but consumes the same power in the same space footprint, he says.

The problem is especially pronounced in urban areas like New York City, says Wambach. In some cases, customers tell him, "I can't physically get more power into my data center, but I still need to do more."

Indirectly, data growth and users' desires for disk-based data protection are inspiring more power-efficient storage designs. "Our design goal was to put 1,000 disk drives in a single box," says Chris Santilli, chief architect and co-founder at Copan Systems. Copan's solution was the massive array of idle disks (MAID) architecture, which only powers on up to 25% of the drives at a time to improve power utilization and extend the life of the disk drives. The result, the Revolution array, fell short of the 1,000 drive goal; but, at 896 drives, it's still approximately four times denser than your average array and uses only one-quarter the power, says Santilli. Given that, "we feature 16 times better power per disk than other systems," he adds. The Revolution is used as a virtual tape library and archiving platform.

But mechanical improvements to storage arrays can only improve power consumption so much, says David Scott, president and CEO at 3PAR. At some point, storage managers need to address the most egregious source of waste: poor utilization.

"Data storage systems are probably the most energy-inefficient systems out there," says Scott. "Average disk utilization rates continue to hang around the 20% to 25% level ... more than half of the disk drives sitting there are effectively wasted," he adds, and consuming unnecessary power.

3PAR's answer to storage power inefficiency is thin provisioning, its oversubscription feature that assigns disk capacity to an application only when it's actually needed, reducing the number of disk drives required in the system.

Warren Habib, CTO at Fotolog, an online content sharing company in New York City and a 3PAR customer, corroborates Scott's claim. With thin provisioning, Fotolog uses 200 fewer disk drives in its system than it would without. Assuming 0.65kWh to power and cool a drive, "with 8,760 hours in a year, we would be using 200 x .065 x 8760 = 113,800 additional kW hours," Habib writes in an e-mail. At a hypothetical cost of $.08 per kWh, "we save $9,110 year and, more importantly, save that much wear and tear on the environment," he notes.

--Alex Barrett