Garbage Collection Technique using Erasure Interval for NAND Flash Memory-based Storage Systems

Recently, many storage systems use SSD based on NAND flash memory, which has many advantages such as low power, low access latency and high reliability. However, NAND flash memory has disadvantages such as erase-beforeprogram, limited P/E cycle, and unbalanced operation latency, compared to conventional magnetic disks. To solve these problems, many works mainly adopt FTL with garbage collection in NAND flash memory systems. However, previous garbage collection techniques are sensitive to the write pattern. In this paper, we propose a garbage collection technique based on the erasure interval, which is called EIGC (Erasure Interval-based Garbage Collection). EIGC is insensitive to the write pattern, compared to other techniques. The proposed technique prolonged the system lifetime about 13% and it reduced the garbage collection overhead about 42.4%, on average. Moreover, our technique reduced the standard deviation about 22.3% on average, compared to other techniques.