Cold-warm-hot block wear-leveling algorithm for a NAND flash storage system

Abstract

Solid state disk has been widely used in various storage system due to fast access speed, good shock resistance, nonvolatile and low power consumption. Generally, solid state storage media is NAND Flash. Because the blocks in a NAND flash have a limited number of erase cycles, this reduces the life of NAND flash. Wear-leveling algorithm is employed to extend the lifetime and reliability of SSDs. In this paper, we propose a novel wear-leveling algorithm based on cold, warm and hot block. First, we divide the cold block and warm block, depending on the erase count of blocks. Second, we extracted the hot data from the warm block and merge them into a new block called hot block. Third, the hot data would be stored into RAM, and warm block and cold block into NAND flash. When we update hot block, we just need to do it in the RAM. According to some experiments with correlative wear-leveling algorithms, this algorithm we propose shows the superiority of similar wear-leveling algorithm.