Arun, BalajiPeluso, SebastianoPalmieri, RobertoLosa, GiulianoRavindran, Binoy2022-01-292022-01-292021-11-011545-5971http://hdl.handle.net/10919/107992Contention 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.Pages 2907-292519 page(s)application/pdfenIn CopyrightTechnologyComputer Science, Hardware & ArchitectureComputer Science, Information SystemsComputer Science, Software EngineeringComputer ScienceConsensus protocolDelaysComputer crashesSwitchesRuntimeFault toleranceDistributed systemsfault toleranceconsensusleaderless consensuscontention-agnostic consensusStrategic, Defence & Security Studies0803 Computer Software0804 Data Format0805 Distributed ComputingArticle - Refereed2022-01-29https://doi.org/10.1109/TDSC.2020.2970186186Ravindran, Binoy [0000-0002-8663-739X]1941-0018