Improving the Reliability of Next Generation SSDs using WOM-v Codes


Shehbaz Jaffer, University of Toronto, Google; Kaveh Mahdaviani and Bianca Schroeder, University of Toronto

Awarded Best Paper!


High density Solid State Drives, such as QLC drives, offer increased storage capacity, but a magnitude lower Program and Erase (P/E) cycles, limiting their endurance and hence usability. We present the design and implementation of non-binary, Voltage-Based Write-Once-Memory (WOM-v) Codes to improve the lifetime of QLC drives. First, we develop a FEMU based simulator test-bed to evaluate the gains of WOM-v codes on real world workloads. Second, we propose and implement two optimizations, an efficient garbage collection mechanism and an encoding optimization to drastically improve WOM-v code endurance without compromising performance. A careful evaluation, including microbenchmarks and trace-driven evaluation, demonstrates that WOM-v codes can reduce the Erase cycles for QLC drives by 4.4x-11.1x for real world workloads with minimal performance overheads resulting in improved QLC SSD lifetime.

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This content is available to:

@inproceedings {277804,
author = {Shehbaz Jaffer and Kaveh Mahdaviani and Bianca Schroeder},
title = {Improving the Reliability of Next Generation {SSDs} using {WOM-v} Codes},
booktitle = {20th USENIX Conference on File and Storage Technologies (FAST 22)},
year = {2022},
isbn = {978-1-939133-26-7},
address = {Santa Clara, CA},
pages = {117--132},
url = {},
publisher = {USENIX Association},
month = feb

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