Solid State Drives: No Flash in the Pan
Hard drive giant Seagate is even suing flash drive front-runner STEC, accusing it of patent violations in this area. STEC counters that Seagate sees the rise of SSD as a big threat to its hard drive business. And the biggest company in storage – EMC – again devoted lots of space to it at its EMC Forum 2008 in Los Angeles this month.
Just two months ago at EMC World, the company displayed a couple of 73 and 146 gigabyte STEC SSDs it had introduced into its higher end Symmetrix arrays. Now SSDs are being put into EMC CLARiiON CX4 midrange arrays. They are 30 times faster than traditional drives, deliver sub-millisecond response times, 58 percent less weight per terabyte, have no moving parts and are 98 percent more energy efficient on an IOPs (Input/Output operations per Second) basis. Thus the company is positioning flash drives as the place for highest performance and/or lowest energy usage storage.
This makes interesting math. To store a terabyte on 73GB fibre channel (FC) drives spinning at 15,000 rpm, you would consume over 6000 kWh per year. A 1TB SATA drive spinning at 5400 rpm, on the other hand, consumes 267 kWh/year. Flash provides a massive boost on FC performance while consuming less power than SATA.
Of course there are downsides, such as cost and durability. Flash was 30 times more expensive than FC in January. Six months later, prices had dropped by 45 percent. Lou Przystas, an advisory consultant at EMC, says that the crossroads will come in the 2010-2011 timeframe as price and performance will mean choosing flash over FC drives.
How about the criticism that flash breaks down under heavy usage? Dave Nicolson, another EMC consultant, says that if you hammer it for several years, the cells will degrade. If you have a write-intensive application, then, flash may not be able to handle it. Testing will determine that. But for most uses, flash seems up to the task. EMC is confident enough to advertise a five-year lifespan.
I’d expect a few well-publicized benchmarks on cell degradation over the next year or two – many of them sourced by hard drive manufacturers. But that will only play into the hands of some startups who will no doubt work out how to solve the heavy-write dilemma. One final fact here on SSD: While EMC heavily promoted its latest arrays, talked up VMware, and discussed enterprise backup and state-of-the-art content management systems, what type of questions dominated? Those about flash drives. Time after time, speakers would make mere mention of flash only for audience members to interrupt with queries. Several in the crowd admitted to having already implemented them.
Nicolson concluded his talk by saying that within a year or two we will all be using them.