Seraph: an efficient, low-cost system for concurrent graph processing

Graph processing systems have been widely used in enterprises like online social networks to process their daily jobs. With the fast growing of social applications, they have to efficiently handle massive concurrent jobs. However, due to the inherent design for single job, existing systems incur great inefficiency in memory use and fault tolerance. Motivated by this, in this paper we introduce Seraph, a graph processing system that enables efficient job-level parallelism. Seraph is designed based on a decoupled data model, which allows multiple concurrent jobs to share graph structure data in memory. Seraph adopts a copy-on-write semantic to isolate the graph mutation of concurrent jobs, and a lazy snapshot protocol to generate consistent graph snapshots for jobs submitted at different time. Moreover, Seraph adopts an incremental checkpoint/regeneration model which can tremendously reduce the overhead of checkpointing. We have implemented Seraph, and the evaluation results show that Seraph significantly outperforms popular systems (such as Giraph and Spark) in both memory usage and job completion time, when executing concurrent graph jobs.