TY - GEN
T1 - Constructing large, durable and fast ssd system via reprogramming 3D TLC flash memory
AU - Gao, Congming
AU - Ye, Min
AU - Li, Qiao
AU - Xue, Chun Jason
AU - Zhang, Youtao
AU - Shi, Liang
AU - Yang, Jun
N1 - Publisher Copyright:
© 2019 Association for Computing Machinery.
PY - 2019/10/12
Y1 - 2019/10/12
N2 - NAND flash memory based SSDs have been widely studied and adopted. The scaling of SSD has evolved from plannar (2D) to 3D stacking. Compared with 2D SSD, 3D SSD stacks more layers into one block, constructing one block with more flash pages. For reliability and other reasons, technology node in 3D NAND SSD is larger than in 2D, but data density can be increased via increasing bit-per-cell. However, representing multiple bits per cell encounters additional challenges such as endurance and access latency. In this work, we develop a novel reprogramming scheme for TLCs in 3D NAND SSD, such that a cell can be programmed and reprogrammed several times before it is erased. Such reprogramming can reduce the frequency of erases which determines the endurance of a cell, improve the speed of programming, and increase the amount of bits written in a cell per program/erase cycle, i.e., effective capacity. Our work is the first to perform real 3D NAND SSD test to validate the feasibility of the reprogram operation. From the collected data, we derive the restrictions of performing reprogramming due to reliability challenges. Further, a reprogrammable SSD (ReSSD) is designed to structure reprogram operations, and when they should be applied. ReSSD is evaluated in a case study in 3D TLC SSD based RAID 5 system (RSS-RAID). Experimental results show that RSS-RAID can improve the endurance by 30.3%, boost write performance by 16.7%, and increase effective capacity by 7.71%, with negligible overhead compared with conventional 3D SSD based RAID 5 system.
AB - NAND flash memory based SSDs have been widely studied and adopted. The scaling of SSD has evolved from plannar (2D) to 3D stacking. Compared with 2D SSD, 3D SSD stacks more layers into one block, constructing one block with more flash pages. For reliability and other reasons, technology node in 3D NAND SSD is larger than in 2D, but data density can be increased via increasing bit-per-cell. However, representing multiple bits per cell encounters additional challenges such as endurance and access latency. In this work, we develop a novel reprogramming scheme for TLCs in 3D NAND SSD, such that a cell can be programmed and reprogrammed several times before it is erased. Such reprogramming can reduce the frequency of erases which determines the endurance of a cell, improve the speed of programming, and increase the amount of bits written in a cell per program/erase cycle, i.e., effective capacity. Our work is the first to perform real 3D NAND SSD test to validate the feasibility of the reprogram operation. From the collected data, we derive the restrictions of performing reprogramming due to reliability challenges. Further, a reprogrammable SSD (ReSSD) is designed to structure reprogram operations, and when they should be applied. ReSSD is evaluated in a case study in 3D TLC SSD based RAID 5 system (RSS-RAID). Experimental results show that RSS-RAID can improve the endurance by 30.3%, boost write performance by 16.7%, and increase effective capacity by 7.71%, with negligible overhead compared with conventional 3D SSD based RAID 5 system.
KW - 3D TLC SSD
KW - Capacity
KW - Endurance
KW - Performance
KW - RAID 5
KW - Reliability
KW - Reprogramming
UR - https://www.scopus.com/pages/publications/85074455194
U2 - 10.1145/3352460.3358323
DO - 10.1145/3352460.3358323
M3 - 会议稿件
AN - SCOPUS:85074455194
T3 - Proceedings of the Annual International Symposium on Microarchitecture, MICRO
SP - 493
EP - 505
BT - MICRO 2019 - 52nd Annual IEEE/ACM International Symposium on Microarchitecture, Proceedings
PB - IEEE Computer Society
T2 - 52nd Annual IEEE/ACM International Symposium on Microarchitecture, MICRO 2019
Y2 - 12 October 2019 through 16 October 2019
ER -