NAND Flash memory would be perfect for nonvolatile storage because except that Flash write speeds are slow enough to create a window of time when write transactions could be lost during a power failure. This problem is especially acute for enterprise-class storage. Skyera’s new 44Tbyte Skyhawk SSD storage system, being exhibited this week at the Flash Memory Summit in Silicon Valley, probably qualifies under the heading of “enterprise-class.”
The Skyera storage system employs Everspin MRAM as a write cache for the system’s main storage medium, consisting of NAND Flash memory. The MRAM’s high write speed is the parameter that allows the MRAM to serve as the storage system’s write cache.
If nonvolatile MRAM were as inexpensive per bit as NAND Flash memory and if it were available in the kinds of bit densities as NAND Flash, there would be no need for the Flash devices at all. However, that’s not the case, so the NAND Flash memory serves as the medium for bulk storage and the MRAM is added in as a cache for the Flash.
If you’d like to hear more about this development, Everspin is presenting the idea in a talk titled “Enabling Write Cache with ST-MRAM” at the Flash Memory Summit on Wednesday, August 22.
Note: This is not the first time that the Denali Memory Report has discussed MRAM as a write cache for NAND Flash storage. See the May 30, 2012 blog post: “MRAM spotted in Buffalo Memory SSD—for cache.”
Update: For more in-depth technical details on the Skyera Skyhawk SSD, see “How Skyera developed the 44Tbyte, enterprise-class Skyhawk SSD from the ground up” in the EDA360 Insider.