C-Lash: A Cache System for Optimizing NAND Flash Memory Performance and Lifetime

NAND flash memories are the most important storage media in mobile computing and tend to be less confined to this area. Nevertheless, it is not mature enough to allow a widespread use. This is due to poor write operations’ performance caused by its internal intricacies. The major constraint of such a technology is the reduced number of erases operations which limits its lifetime. To cope with this issue, state-of-the-art solutions try to level the wear out of the memory to increase its lifetime. These policies, integrated into the Flash Translation Layer (FTL), contribute in decreasing write operation performance. In this paper, we propose to improve the performance and reduce the number of erasures by absorbing them throughout a dual cache system which replaces traditional FTL wear leveling and garbage collection services. C-lash enhances the state-of-the-art FTL performance by more than an order of magnitude for some real and synthetic workloads.