DIDACache: A Deep Integration of Device and Application for Flash Based Key-Value Caching

Zhaoyan Shen, Hong Kong Polytechnic University; Feng Chen and Yichen Jia, Louisiana State University; Zili Shao, Hong Kong Polytechnic University


In recent years, flash-based key-value cache systems have raised high interest in industry, such as Facebook’s McDipper and Twitter’s Fatcache. These cache systems typically use commercial SSDs to store and manage key-value cache data in flash. Such a practice, though simple, is inefficient due to the huge semantic gap between the key-value cache manager and the underlying flash devices. In this paper, we advocate to reconsider the cache system design and directly open device-level details of the underlying flash storage for key-value caching. This co-design approach bridges the semantic gap and well connects the two layers together, which allows us to leverage both the domain knowledge of key-value caches and the unique device properties. In this way, we can maximize the efficiency of key-value caching on flash devices while minimizing its weakness. We implemented a prototype, called DIDACache, based on the Open-Channel SSD platform. Our experiments on real hardware show that we can significantly increase the throughput by 35.5%, reduce the latency by 23.6%, and remove unnecessary erase operations by 28%.

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@inproceedings {202262,
author = {Zhaoyan Shen and Feng Chen and Yichen Jia and Zili Shao},
title = {DIDACache: A Deep Integration of Device and Application for Flash Based Key-Value Caching},
booktitle = {15th {USENIX} Conference on File and Storage Technologies ({FAST} 17)},
year = {2017},
isbn = {978-1-931971-36-2},
address = {Santa Clara, CA},
pages = {391--405},
url = {https://www.usenix.org/conference/fast17/technical-sessions/presentation/shen},
publisher = {{USENIX} Association},