Strong and Efficient Consistency with Consistency-Aware Durability


Aishwarya Ganesan, Ramnatthan Alagappan, Andrea Arpaci-Dusseau, and Remzi Arpaci-Dusseau, University of Wisconsin–Madison
Awarded Best Paper!


We introduce consistency-aware durability or CAD, a new approach to durability in distributed storage that enables strong consistency while delivering high performance. We demonstrate the efficacy of this approach by designing cross-client monotonic reads, a novel and strong consistency property that provides monotonic reads across failures and sessions in leader-based systems. We build ORCA, a modified version of ZooKeeper that implements CAD and cross-client monotonic reads. We experimentally show that ORCA provides strong consistency while closely matching the performance of weakly consistent ZooKeeper. Compared to strongly consistent ZooKeeper, ORCA provides significantly higher throughput (1.8 – 3.3×), and notably reduces latency, sometimes by an order of magnitude in geo-distributed settings.

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@inproceedings {246164,
author = {Aishwarya Ganesan and Ramnatthan Alagappan and Andrea Arpaci-Dusseau and Remzi Arpaci-Dusseau},
title = {Strong and Efficient Consistency with {Consistency-Aware} Durability},
booktitle = {18th USENIX Conference on File and Storage Technologies (FAST 20)},
year = {2020},
isbn = {978-1-939133-12-0},
address = {Santa Clara, CA},
pages = {323--337},
url = {},
publisher = {USENIX Association},
month = feb,

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