Buckle up -- SSDs are about to get up to four times faster

A Japanese research team uses a write algorithm that can be added to existing drives to get past performance bottlenecks

A team of Japanese researchers claims to have developed technology that improves write speeds on solid-state drives by 300 percent using nothing more sophisticated than a firmware patch, according to a TechOn report.

In a thesis entitled "NAND Flash Aware Data Management System for High-Speed SSDs by Garbage Collection Overhead Suppression," Ken Takeuchi, a professor at Chuo University in Tokyo, laid out his team's ideas for dealing with a common performance bottleneck in SSDs -- namely, garbage collection.

Garbage collection is an artifact of the way data is stored on an SSD. Changes made to data on an SSD must be written in a two-step process. First, the changed data has to be written to an already empty 4KB page of memory; second, the old version of the data has to be erased. Because SSDs can only erase data in 256KB chunks called blocks (individual memory pages can't be erased) the written data must be consolidated in a different block before the space used by the old data can be reclaimed.

While garbage collection is generally a lot faster than defragmenting a conventional mechanical drive, it still can cause performance bottlenecks, especially on drives that receive a many write operations. And with flash storage becoming more widely deployed in enterprises, a long-term solution for such bottlenecks is needed.

Takeuchi's proposed solution, which can be employed in a drive without changing the way its memory cells work (although they might also require an OS-level device driver), involves more scrupulous control over where the data is written so that fewer copying operations need to be performed before a block can be erased. In test simulations, the proposed algorithm was believed to have increased write speeds by 300 percent and cut the number of write/erase cycles by more than half.

Most of the speed improvements for SSDs in enterprise environments revolve around the data connection used by the drive. Aside from drives that attach directly to the PCI backplane, some other novel approaches have surfaced. IBM, for instance, has tried placing SSDs in DIMM slots, so the SSDs can use the system's much faster memory channel rather than its PCI bus. But if the bottlenecks are inside the drives themselves, only so much work can be done on the outside to speed them up.

[An earlier version of this article was entitled "Buckle up -- SSD are about to get three times faster." The maximum speed-up of 300% described by the researchers equates to being four times faster, not three.]

This story, "Buckle up -- SSDs are about to get up to four times faster," was originally published at InfoWorld.com. Get the first word on what the important tech news really means with the InfoWorld Tech Watch blog. For the latest developments in business technology news, follow InfoWorld.com on Twitter.

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