If you are considering migrating to flash SSD storage, you need to understand that there are two types of flash SSD. There are single-layer cell (SLC) NAND flash chips and multiple-layer cell (MLC) NAND flash chips. Essentially, MLC is less expensive and offers more capacity than SLC though SLC is generically faster. A knock on MLC is that the chips wear out quicker than SLC chips because additional work is required by the controller accessing the additional capacity.
Teresa Worth of Seagate Technology published a byline article in EE Times about this topic ultimately concluding that “with advances in MLC controller technology, SSD vendors have been able to improve endurance and reliability to a level that meets enterprise requirements while retaining MLC’s cost advantages.”
We agree with this assessment though we think in addition to controller technology, there are other innovations enabling MLC chips to be more attractive to the enterprise market.
Kaminario uses MLC flash in its K2 all solid-state storage devices. One of the ways we extend MLC life is through our Scale-out Performance Storage Architecture (SPEAR) that we have discussed in previous posts. SPEAR enables dynamic load balancing and automated data distribution across multiple DataNodes, reducing wear. Plus, SPEAR offers intelligent parallel I/O processing meaning that I/O requests are distributed across the K2 storage cluster smartly parallelizing all reads and writes increasing performance and preventing hot spots.
So yes, Ms. Worth is correct that there are now viable MLC flash SSD options for enterprises. To us, it is architecture and software that is helping to drive this change.