A panel discussion on enterprise SSDs at the Flash Memory Summit came to an almost unanimous conclusion: NAND flash is best seen as an extension to DRAM and a layer between DRAM and disk – not as the guts of a disk drive replacement.
I don’t think the guy from Seagate agreed.
Since I was on the panel, my recollections have to be taken with grain of salt. But I was trying to resist the group think that too many panels fall prey to. Yet I agreed with the result.
Price changes everything
StorageMojo has reported at length on the problems of making a big, quirky EEPROM look like a disk. Flash doesn’t look much like DRAM either, but the two are cousins.
In the last few years price has altered the landscape. On today’s spot market a Gbit of DRAM is 7-10x of a Gbit of MLC NAND.
That wasn’t the case 3 years ago, so substituting flash for DRAM made no sense.
The market resistance to flash drives is because flash costs more than disk. Not a problem when augmenting DRAM.
The performance fit
Disks are millisecond devices; DRAM DIMMs are nanosecond devices; and NAND chips are microsecond devices.
More than once it was suggested that maybe it is time to bring back the 3600 RPM drive. Optimized for capacity, power and long life, it would be a good complement to servers with several hundred GB of flash.
The StorageMojo take
Flash as a new storage layer between DRAM and disk just sounds more logical than flash-as-a-disk-like product. Let disks be disks!
And flash be flash.
Courteous comments welcome, of course. More on this topic later. Stay tuned.