New ERA: New Efficient Reliability-Aware Wear Leveling for Endurance Enhancement of Flash Storage Devices

As the program/erase (P/E) cycles of flash memory keep decreasing, improving the lifetime/endurance of flash memory has become a fundamental issue in the design of flash devices. This work is motivated by the observation that flash blocks endured the same P/E cycles usually have different bit error rates. In contrast to the existing wear-leveling techniques that try to distribute erases to flash blocks as evenly as possible, we propose an efficient reliability-aware wear-leveling scheme to distribute block erases based on the bit error rates of blocks so as to even out the error rate among flash blocks, to maximize the number of good blocks, and thus to ultimately prolong the lifetime of flash storage devices. The experiments were conducted based on representative realistic workloads to evaluate the efficacy of the proposed scheme, for which the results are very encouraging.