Fireplug: Flexible and robust N-version geo-replication of graph databases

The paper describes and evaluates Fireplug, a flexible architecture to build robust geo-replicated graph databases. Fireplug can be configured to tolerate from crash to Byzantine faults, both within and across different datacenters. Furthermore, Fireplug is robust to bugs in existing graph database implementations, as it allows to combine multiple graph databases instances in a cohesive manner. Thus, Fireplug can support many different deployments, according to the performance/robustness tradeoffs imposed by the target application. Our evaluation shows that Fireplug can implement Byzantine fault tolerance in geo-replicated scenarios and still outperform the built-in replication mechanism of Neo4j, which only supports crash faults.