Strengthening Consistency in the Cassandra Distributed Key-Value Store
AUTHORS: Panagiotis Garefalakis, Panagiotis Papadopoulos, Ioannis Manousakis and Kostas Magoutis.
In Proceedings of 13th IFIP International Conference on Distributed Applications and Interoperable Systems (DAIS 2013), Florence, Italy, 3-6 June 2013.
ABSTRACT
Distributed highly-available key-value stores have emerged as important building blocks for applications handling large amounts of data. The Apache Cassandra system is one such popular store combining a key distribution mechanism based on consistent hashing with eventually-consistent data replication and membership mechanisms. Cassandra fits well applications that share its semantics but is a poor choice for traditional applications that require strong data consistency. In this work we strengthen the consistency of Cassandra through the use of appropriate components: the Oracle Berkeley DB Java Edition High Availability storage engine for data replication and a replicated directory for maintaining membership information. The first component ensures that data replicas remain consistent despite failures. The second component simplifies Cassandra’s membership, improving its consistency and availability. In this short note we argue that the resulting system fits a wider range of applications, and is more robust and easier to reason about.
