Lifetime Management of Flash-Based SSDs Using Recovery-Aware Dynamic Throttling

NAND flash-based solid-state drives (SSDs) are increasingly popular in enterprise server systems because of their advantages over hard disk drives such as higher performance and lower power consumption. However, the limited and unpredictable lifetime of SSDs remains to be a serious obstacle to wider adoption of SSDs in enterprise systems. In this paper, we propose a novel recovery-aware dynamic throttling technique, called READY, which guarantees the SSD lifetime required by the enterprise market while exploiting the self-recovery effect of floating-gate transistors. Unlike a static throttling technique, the proposed technique makes throttling decisions dynamically based on the predicted future write demand of a workload so that the required SSD lifetime can be guaranteed with less performance degradation. The proposed READY technique also considers the self-recovery effect of floating-gate transistors which improves the endurance of SSDs, enabling to guarantee the required lifetime with less write throttling. Our experimental results show that the proposed READY technique can improve write performance by 4.4x with less variations on the write time over the existing static throttling technique while guaranteeing the required SSD lifetime.