Cellrejuvo: Rescuing the Aging of 3D Nand Flash Cells with Dense-Sparse Cell Reprogramming

3D NAND flash memory is one of the most important storage technologies in modern computer systems because of its non-volatile nature and excellent data access performance. However, it suffers from aging and reliability issues due to its inherent property. In contrast to the previous research that tried to recover the data with additional encoding techniques, we propose a novel reprogramming technique, called CellRejuvo, to improve the reliability of NAND flash cells. To the best of our knowledge, CellRejuvo is the pioneer for data recovery technique that cleverly leverages reprogramming to alleviate cell aging, extending the lifespan of solid-state drives. We implement CellRejuvo on a real 3D NAND flash-based SSD and evaluate its capability on various realistic workloads. The extensive experimental results show that CellRejuvo successfully reduces the error rate of SSD by an average of 38.28 % under various retention times.