Recently, Steve Lohr of the New York Times wrote an interesting article titled, “Demand for Data Puts Engineers in Spotlight” . A paragraph of particular interest states, “The problem is that most computers in data centers run at 15 percent or less of capacity on average, loafing the rest of the time, though consuming electricity all the while. (In the old days, when they housed a few large computers, data centers were far more efficient. Mainframe computers run at 80 percent of capacity or more).”
This corroborates my almost two decades of experience in disk storage. While many administrators believe their storage systems operate 24×7, most do not, and in fact few storage systems do. At Nexsan’s suggestion, one customer turned on AutoMAID (Nexsan’s proprietary energy-saving technology that reduces disk drive energy when disks are idle) to Level 1, the first of three levels of energy savings. After a short period of time, he was surprised to find that his storage system supporting an important and frequently used application was idle more often than he thought. In fact, he was able to save 20% on energy without ever experiencing an application delay or receiving a complaint from a user, because the disks sprang back to full power without a drop in performance every time an I/O request interrupted their idle state.
Like computers, if storage systems are accessed only 15% of the time, they spin disks 100% of the time. I like car analogies, so here goes another one: this reminds me of sitting at a red light and revving your car engine to high RPMs while you wait for the light to turn green.
No one would do that for long, so why do that with your storage systems?
One of the first steps in reducing storage energy consumption is making storage administrators aware that their systems are idle a lot more than they think. Far too many administrators are wasting large amounts of energy (and, of course, money) because they think their storage systems need to run at full power 24×7. Realizing the secret that storage is idle at times (especially on nights and weekends) is the first step towards significant savings.
