Design Tradeoffs for SSD Reliability


Bryan S. Kim, Seoul National University; Jongmoo Choi, Dankook University; Sang Lyul Min, Seoul National University


Flash memory-based SSDs are popular across a wide range of data storage markets, while the underlying storage medium—flash memory—is becoming increasingly unreliable. As a result, modern SSDs employ a number of in-device reliability enhancement techniques, but none of them offers a one size fits all solution when considering the multi-dimensional requirements for SSDs: performance, reliability, and lifetime. In this paper, we examine the design tradeoffs of existing reliability enhancement techniques such as data re-read, intra-SSD redundancy, and data scrubbing. We observe that an uncoordinated use of these techniques adversely affects the performance of the SSD, and careful management of the techniques is necessary for a graceful performance degradation while maintaining a high reliability standard. To that end, we propose a holistic reliability management scheme that selectively employs redundancy, conditionally re-reads, judiciously selects data to scrub. We demonstrate the effectiveness of our scheme by evaluating it across a set of I/O workloads and SSDs wear states.

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@inproceedings {227802,
author = {Bryan S. Kim and Jongmoo Choi and Sang Lyul Min},
title = {Design Tradeoffs for {SSD} Reliability},
booktitle = {17th {USENIX} Conference on File and Storage Technologies ({FAST} 19)},
year = {2019},
isbn = {978-1-931971-48-5},
address = {Boston, MA},
pages = {281--294},
url = {},
publisher = {{USENIX} Association},