• SNIA Home
• Forums & Initiatives
• Solid State Storage Initiative
• Programs
• Knowledge Center
  • Research
  • Education
  • Articles
• News and Events
• About
  • Mission & Charter
  • Leadership
  • Members
  • Join SSSI

Solid State Storage Initiative (SSSI)

Companies are taking a tested and successfully applied idea - high speed memory used as storage - and a new low cost persistent memory technology - NAND Flash - to create storage systems that finally have the ability to close the server/storage performance gap at a reasonable cost. This performance gap exists today because servers have become increasingly faster while storage systems, which use Hard Disk Drives (HDDs) that require rotating disks and mechanical movement of the read/write heads, have not kept up. Servers have to spend a significant portion of their time waiting on storage I/O operations to complete, thus negatively impacting system and application performance.

This movement is occurring now because of the last few years' advent of consumer products made from or integrating NAND Flash, like USB thumb drives, iPods, MP3 players, digital cameras, and cell phones. The number of these products consumed around the world annually is nothing short of astounding. These economies of scale have resulted in rapidly decreasing cost curves which opened up new opportunities for the use of NAND Flash in storage systems. Continued innovations along with lithography and process advancements in Flash memory and its supporting ecosystem have led to an almost annual doubling of Flash components available to the marketplace.

A memory technology that can only be written so many times before it starts to "forget" seems like it would be a poor choice for storage. However, researchers and engineers around the world have been diligently working on addressing this problem over several years and have delivered various enhancements that successfully prevent applications and end users from ever hitting this write limit, even in heavy write environments.

One of the earliest enhancements was the invention of "wear-leveling", a term used to describe the process of making sure that all of the writes are spread evenly across the entire memory module, in order to eliminate any hot spots. Another enhancement was the addition of spare blocks to aid in spreading the writes across a larger amount of memory, further delaying the write limit of a Flash module. Additional enhancements include the use of a small RAM cache used to reduce the number of underlying write operations to a Flash module. Finally, sophisticated Error Correction Codes (ECC), module sparing, and modules configured in a "RAID-like" manner are further examples of innovations developed to extend the longevity and endurance of the NAND Flash storage media beyond typical application cycle life-spans.

Pictures from the SSSI Meeting in Dallas at SNW Fall 2008: