GuardedErase - Extending SSD Lifetimes by Protecting Weak Wordlines

Explore a cutting-edge approach to extending SSD lifetimes in this conference talk from FAST '22. Delve into the GuardedErase scheme, a novel block erase technique designed to mitigate process variability issues in 3D NAND flash memory. Learn how this innovative method delays the wear-out of weak wordlines by reducing applied erase voltages, effectively maximizing flash block endurance. Discover the proposed hardware design that enables selective control of erase voltage levels for individual wordlines. Gain insights from an extensive characterization study using real 3D flash chips, which led to the development of a new NAND endurance model. Examine nine different GuardedErase modes optimized for flash lifetime extension without compromising I/O performance. Understand the implementation of GuardedErase-aware FTL, called longFTL, and its potential to improve SSD lifetime by an average of 21% compared to existing FTLs. This talk presents valuable information for professionals and researchers in the field of storage technology and SSD optimization.