Parqua: Online Reconfigurations in Virtual Ring-Based NoSQL Systems

The performance of key-value/NoSQL storage systems is highly tied to the choice of (primary) key for the database table. As application requirements change over time, system administrators need to change the primary key of the table to improve performance. The primary key change is a specific example of a broader class of reconfiguration operations that affect a lot of data all at once. In this paper we propose a system called Parqua, which imbues ring-based key-value/NoSQL stores with the ability to perform reconfiguration operations in an online and efficient manner. We present the design and implementation of Parqua. Experiments based on our cluster deployments show that during reconfiguration Parqua maintains high availability, and with a small impact on read and write latencies.