Improving performance and lifetime of NAND storage systems using relaxed program sequence

Abstract

We propose a new system-level solution that improves both the performance and lifetime of NAND storage systems by exploiting the performance asymmetry of NAND devices. At the device level, we propose a new program sequence, called relaxed program sequence (RPS), which allows more flexible page allocations in a block without compromising NAND reliability. By combining RPS with per-block parity pages, we can improve the write bandwidth and eliminate expensive paired page backup operations. Experimental results show that the proposed technique can increase IOPS by up to 56% and reduce the number of block erasures by up to 30% over an existing RPS-oblivious FTL.