With the cost of electricity soaring by 30% to 60% this year, IT
managers are looking for ways to make their storage systems more
efficient.
EMC for example, has seen a surge in interest for 500GB disc
drives in its Symmetrix DMX platforms, according to 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 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 datacentre, but I still
need to do more."
Indirectly, data growth and users' desires for disc-based data
protection are inspiring more power-efficient storage designs.
"Our design goal was to put 1,000 disc drives in a single box,"
said Chris Santilli, chief architect and co-founder at Copan
Systems. Copan's product uses a
massive array of idle disks (MAID)
architecture, which only powers on up to 25% of the drives at a
time to improve power utilisation and extend the life of the
disc 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 an average array and uses only one quarter the power,
Santilli said. Given that, "we feature 16 times better power per
disc than other systems," he added. The Revolution is used as a
virtual tape library (VTL) and archiving
platform.
But mechanical improvements to storage arrays can only improve
power consumption so much, said David Scott, president and CEO at
3Par Data. At some point, storage managers need to address the most
egregious source of waste - poor utilisation.
"Data storage systems are probably the most energy-inefficient
systems out there," Scott said. "Average disk utilisation rates
continue to hang around the 20% to 25% level. More than half of the
disc drives sitting there are effectively wasted," he added.
3Par's answer to storage power inefficiency is
thin provisioning, its oversubscription
feature that assigns disc capacity to an application only when
it's actually needed, reducing the number of disc drives
required in the system.
Warren Habib, chief technology officer at Fotolog, an online
content sharing company in New York and a 3Par customer,
corroborated Scott's claim. With thin provisioning, Fotolog uses
200 fewer disc 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 said. 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.