The cloud, brought to you by flash storage
- — 11 August, 2009 06:53
Cloud computing and flash-based storage, two of the fastest-growing technologies in IT, may drive each other forward as Internet-based service providers demand faster access to large amounts of data.
Flash storage has lower reading latency than hard disk drives because it doesn't need to spin a disk to get to a particular bit of data. With SSDs (solid-state disks) and PCI Express flash cards, it's possible to read data anywhere in the device in less than a millisecond, compared with several milliseconds on a hard drive.
This can have some utility in individual enterprises, but the real benefit comes at the scale of public cloud computing, where one service provider may be delivering data to hundreds or thousands of customers at the same time.
Though flash still has some hurdles to overcome on the road to wide deployment, some Web-based services companies see it as the most promising advance happening in IT infrastructure.
"In the last 20 years, spinning disk really hasn't gone any faster, and right now we're really on the cusp of a change with flash technologies," said Richard Buckingham, vice president of technical operations at MySpace, at the Structure conference in June in San Francisco.
MySpace rival Facebook praised flash at the same conference.
"Flash is going to have a very, very significant effect on not just storage, but infrastructure as a whole. And I think it's going to have at least as significant an impact as going from single-core to multicore CPUs," said Facebook Vice President of Technical Operations Jonathan Heiliger.
Internet-based companies expect to use flash in different ways, but scale is a major concern for all of them. It's this factor that could turn flash into the game-changer at online companies that it won't be for most enterprises, according to Forrester Research analyst Andrew Reichman.
SSDs and flash storage cards take up less space and power than spinning disks, even while they deliver bits faster. Cloud-based companies' data centers are so big that these benefits really matter, he said.
"If it was just a single company, the likelihood is that the performance would matter less," Reichman said.
Solid-state storage has long been a part of data centers that need low latency. Since the 1990s, financial firms and other companies have stored large amounts of transaction data in DRAM for quick access, said storage consultant Tom Coughlin.
Flash isn't quite as fast as DRAM, but it's less expensive, uses less power and holds onto its contents whether it's powered or not. As a result, IT managers are starting to see it as a more affordable path to fast reads of certain types of information, such as metadata, transaction data and bits needed for transactions.
Even online entertainment companies are starting to get interested in flash storage for their content, Coughlin said. Flash is available in both SSDs, which come in the same form factor as hard drives, and smaller flash cards from vendors such as Fusion-io, which can be plugged directly into servers using PCI Express interfaces.
Most enterprise flash is made with a single-level architecture, which is more expensive and not quite as dense as the multilevel flash used in consumer devices such as iPods.
Multilevel flash uses different levels of voltage for different bits of data, which allows more densely packed data but requires extra management that reduces real-world performance, Coughlin said. Many observers consider single-level more reliable and less prone to losing capacity over long periods of heavy use.