Hitachi Accelerated Flash Storage Ignites Flash From Enlightenment to Productivity
by Hu Yoshida on Nov 7, 2012
Most everyone in the storage business is familiar with the Gartner Hype Cycle for Storage Technologies. When prospective game-changing technologies start, they rise to the peak of inflated expectations, then fall into the trough of disillusionment, before they gradually climb the slope of enlightenment and eventually reach the plateau of productivity. In the Gartner July 2012 Hype Cycle for Enterprise Storage, solid-state drives (SSDs) were still sitting on the slope of enlightenment, slightly ahead of where they were last year.
Today Hitachi Data Systems announces Hitachi Accelerated Flash storage, which will take flash to higher levels of performance, durability, capacity and cost, propelling flash onto the plateau of productivity.
At the end of 2011 there were rosy predictions of doubling SSD growth, and while it might be true of the non-enterprise SSD market, this last quarter saw enterprise SSD vendors falling behind last year’s results. SearchStorage.com and Storage Magazine surveyed users this fall and found that just 14% used SSDs, mainly in storage arrays. Of the non-users, two-thirds said that the main reason was that SSDs were too expensive. While price is a key factor, TCO is also a concern if the durability of flash requires more frequent spare outs, which increases operational as well as capital costs. Other web posts recount stories of flash write performance falling off a cliff when housekeeping is initiated to recover invalid pages for reuse.
Keying off the Gartner Hype Chart, Rich Castagna issued a warning on SearchStorage.com. Beware: Solid State Storage Approaching the Valley of Vagueness.
In this article he said that “solid state storage is at the point where confusion is threatening to overtake the technology itself and we who follow this market find ourselves teetering on the brink of the valley of vagueness.” He noted that the differences in systems using SLC flash and MLC flash could be hugely important and the vocabulary that vendors use to equate the cost of SSD to HDD leaves him wondering what the ROI really is. Vendors who address durability by claiming they can write 33 PB of data to 600 GB drives 30 times a day for 5 years leaves him wondering what the real failure rate in production use could be. As a result, enterprise SSDs have appeared to be slipping down the slope of enlightenment in recent months.
Today’s announcement of Hitachi Accelerated Flash storage should take away all the vagueness around flash storage as far as Hitachi systems are concerned. Hitachi has built its own multi-core embedded flash controller, with inline write compression capability, to eliminate the problems of MLC versus SLC performance, the ominous write cliff, limited durability, and high price. With the Hitachi controller MLC flash outperforms SSDs with SLC flash, the garbage collection and housekeeping is taken out of the I/O path to eliminate the write cliff, and durability of MLC flash is extended with no restrictions because the compression feature reduces physical writes on the flash memory by up to 94 percent. The main benefit of this controller is the ability to handle larger capacities of flash, which makes the price of Hitachi Accelerated Flash storage up to 46 percent less than MLC flash SSD configurations. This also brings the price of Hitachi Accelerated Flash storage within 4 times the price of high-performance SAS HDDs. For a customer, the decision to use flash at 4 times the cost of an HDD is much easier to make than when it was 10 times the cost. This could reinvigorate the enterprise flash market and accelerate its movement to the plateau of productivity.
The secret sauce is in the embedded flash controller from Hitachi, Ltd., which was designed and intentionally built for the demands of the enterprise market. Until now, SSD vendors have been designing flash controllers for the PC market, where all the volumes are, and leveraging them in the enterprise market. Building our own enterprise flash controller was natural for Hitachi engineering whose reputation is built on innovative controller and backplane technologies. For a description of some of the problems we solved with this new controller and packaging for the Hitachi Accelerated Flash storage, see my post from September 5.
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[...] continue as before. The controller provides inline compression, and HDS vice-president Hu Yoshida said this “reduces physical writes on the flash memory by up to 94 per [...]
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