Flash memory won its edge than other storage media for its advantages, such as shock resistance, low power consumption and high data transmission speed. However, new data is written out-of-place due to the characteristics of flash memory, which is diverse from traditional magnetic media. Out-of-place update results in the wear-leveling issue over flash memory for erasing blocks to reclaim invalid pages. This paper proposed a dynamic wear (DW)-leveling design without substantially increasing overhead and without modifying Flash Translation Layer (FTL) for huge-capacity flash storage systems with cache, which is based on segmentation threshold and Least Recently Used (LRU). Experimental results show that our design levels the wear of different physical blocks, reduces extra page coping and block erasing, and improves the read/write performance. Additionally, different thresholds impacting wear leveling are also discussed.

SUMMARYThe wear leveling is a critical factor which significantly impacts the lifetime and the performance of flash storage systems. To extend lifespan and reduce memory requirements, this paper proposed an efficient wear leveling without substantially increasing overhead and without modifying Flash Translation Layer (FTL) for huge-capacity flash storage systems, which is based on selective replacement. Experimental results show that our design levels the wear of different physical blocks with limited system overhead compared with previous algorithms.