Taming the Contention in Consensus-Based Distributed Systems


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Contention plays a crucial role in the design of consensus protocols. State-of-the-art solutions optimize their performance for either very low or high contention situations. We propose Caesar, a novel multi-leader Generalized Consensus protocol, most suitable for geographical replication, that is optimized for low-to-moderate contention. With an evaluation study, we show that Caesar outperforms other multi-leader (e.g., EPaxos) and single-leader (e.g., Multi-Paxos) competitors by up to 1.7x and 3.5x, respectively, in the presence of 30 percent conflicting requests, in a geo-replicated setting. Furthermore, we acknowledge that there is no one-size-fits- all consensus solution, especially for all levels of contentious workloads. Thus, we also propose Spectrum, a consensus framework that is able to switch consensus protocols at runtime to enable a dynamic reaction to changes in the workload and deployment characteristics. We show empirically that Spectrum can guarantee high availability even during periods of transition between consensus protocols.



Technology, Computer Science, Hardware & Architecture, Computer Science, Information Systems, Computer Science, Software Engineering, Computer Science, Consensus protocol, Delays, Computer crashes, Switches, Runtime, Fault tolerance, Distributed systems, fault tolerance, consensus, leaderless consensus, contention-agnostic consensus, Strategic, Defence & Security Studies, 0803 Computer Software, 0804 Data Format, 0805 Distributed Computing