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"I had to unrack a server just to put some new SAN storage in; I had no space left, period," says Wooley. Nielsen Mobile's data center owners were "annoyed with how much power we were using," he adds. The company pays approximately $20,000 per month in power and cooling costs to its co-location data center, about the same as its rent.
Wooley evaluated Copan Systems Inc., the company that premiered the first massive array of idle disks (MAID) technology, which packs a large number of disks into a small space and minimizes power and cooling by only powering up active drives. "They didn't have a file system," he says. "It wasn't the bottom line, but it was important." Instead, Wooley purchased a PowerFile Inc. Active Archive Appliance (A3), which includes compression technology and Blu-ray disk for archival storage.
Before purchasing the PowerFile A3, Nielsen Mobile's Wooley compared its power consumption with a NetApp R200 "because that's what we were using for archiving." According to him, "the NetApp
| unit has a lot more functionality than the PowerFile A3 and performs better, so this wasn't an apples-to-apples comparison; but for my intended use [long-term archive of infrequently accessed files], I think it makes sense."
Here are Wooley's back-of-the-napkin calculations, done to determine power use and cost, provided with the caveat that he wasn't looking for high-performance storage for active files and that NetApp performs much better. "Both the NetApp R200 and the PowerFile A3 have a head unit, each draws about 300W to 350W, so I left them out of the calculation and only looked at the power used by incremental storage. In my R200, four DS14mk2 shelves yield 10.7TB usable space after RAID and online spares (though newer models may offer more density/watt). Let's say each shelf draws about 350W. That works out to about 130W/TB (4*350W)/10.7TB). A PowerFile A3 library holds 10TB usable space and uses 8W, which works out to 0.8W/TB online. (Offline is obviously 0W/TB.) So, 20TB of R200 disk will draw about 2,900W ((130W/TB*20) + 300W/head) and 20TB of PowerFile about 316W ((0.8W/TB*20) + 300). That's a pretty significant savings, and if I add in the 10TB I have sitting in a drawer offline, it seems even better."
This was first published in October 2008