EMC Corp., for example, has seen a surge in interest for 500 GB disk drives in its Symmetrix DMX platforms, according to Bob Wambach, director of EMC Symmetrix product marketing. The reason? A 500 GB drive offers 66% more capacity than a 300 GB version but consumes the same power in the same space footprint, he said.
The problem is especially pronounced in urban areas like New York City, Wambach said. In some cases, customers tell him, "I can't physically get more power into my data center, but I still need to do more."
But mechanical improvements to storage arrays can only improve power consumption so much, said David Scott, president and CEO at 3Par Data Inc.. 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," Scott said. "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 added, 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, chief technology officer at Fotolog Inc., an online content sharing company in New York City and a 3Par customer, corroborated Scott's claim. With thin provisioning, Fotolog uses 200 fewer disk drives in its system than it would without. Assuming 0.65 kWh 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 kilowatt hours," Habib wrote in an email. At a hypothetical cost of $.08 kWh, "we save $9,110 year and, more importantly, save that much wear and tear on the environment," he noted.