Search This Blog

Wednesday, March 25, 2009

NAND Flash Memory and Its Role in Storage Architectures

NAND Flash Memory and Its Role in Storage Architectures
Marco A. A. Sanvido, Frank R. Chu, Anand Kulkarni, and Robert Selinger

NAND flash technology
Reliability and failure mechanism – Wearout, retention, write disturb, and read disturb
Environmental factors – high density, relatively low entry costs, low power consumption, and robust characteristics with regards to response to shock and vibrations and wide range of ambient temperatures
Disk Caching architectures – Hybrid HDD, External Caching (Turbo Memory), and Non Volatile Memory Hardware Controller Interface (NVMHCI)
Solid State Drives (SSD)

Most server environments contain terabytes of capacity, so significant usage of flash is not affordable in the foreseeable future, NAND flash may be used in place of some of the DRAM caches used in storage subsystems, since it has a lower cost per bit and is nonvolatile without relying on batteries. However, most server data does not have the same locality as PC programs and user data, so caching approaches (e.g. hybrid HDDs) may not be as useful in server workloads. And if the caching is successful, then the higher I/O rates may create greater problems of wearout for flash.

No comments:

Post a Comment

Blog Archive