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Seminar: Consistency and Performance in Distributed Storage Systems

Aishwarya Ganesan

Postdoctoral Researcher, VMware Research Group

Thursday, January 27, 2022
10:00 AM
Via Zoom



Computer systems underpin every modern application that we interact with today. When designing systems, one must often tradeoff strong guarantees for performance or vice-versa. The same tradeoff exists in distributed storage systems as well; designers must often choose consistency or performance. In this talk, I will show how we can build distributed storage systems that provide strong consistency yet also perform well. My key insight to achieving this goal is to defer enforcing consistency until state is externally visible. Based on this insight, I design two novel distributed storage systems.

First, I present Skyros, a new replication protocol that exploits storage-interface properties to defer expensive coordination. Skyros realizes that many update interfaces are nil-externalizing: they do not expose system state immediately. By taking advantage of nil-externality, Skyros offers significantly lower latencies than traditional replication protocols while still providing strong consistency.

Second, I present consistency-aware durability (CAD), a new durability primitive that enables stronger consistency. CAD shifts the point of durability from writes to reads. By delaying writes, CAD enables high performance; however, by ensuring durability before serving reads, CAD enables the construction of stronger consistency models.


Aishwarya Ganesan is a postdoctoral researcher at VMware Research. She recently completed her PhD from the University of Wisconsin - Madison, advised by Andrea Arpaci-Dusseau and Remzi Arpaci-Dusseau. She is broadly interested in distributed systems and storage systems. Her work has been recognized with best-paper awards at FAST 20 and FAST 18 and a best paper award nomination at FAST 17. She was selected for the Rising Stars in EECS workshop and a recipient of Facebook 2019 PhD Fellowship. She also received the graduate student instructor award for teaching graduate-level distributed systems at UW Madison.