RAMS: a RDMA-enabled I/O cache architecture for clustered network servers

Previous studies show that intra-cluster communication easily becomes a major performance bottleneck for a wide range of small write-sharing workloads especially read-only workloads in modern clustered network servers. A Remote Direct Memory Access (RDMA) technique has been recommended by many researchers to address the problem but how to well utilize RDMA is still in its infancy. This paper proposed a novel solution to boost intra-cluster communication performance by creatively developing a RDMA-enabled collaborative I/O cache Architecture called RAMS, which aims to smartly cache the most recently used RDMA-based intra-cluster data transfer processes for future reuse. RAMS makes two major contributions to facilitate the RDMA deployment: 1) design a novel RDMA-based user-level buffer cache architecture to cache both intra-cluster transferred data and data references; 2) develop three propagated update protocols to attack a RDMA read failure problem. Comprehensive experimental results show that three proposed new update protocols of RAMS can slash the RDMA read failure rate by 75%, and indirectly boost the system throughput by more than 50%, compared with a baseline system using Remote Procedure Call (RPC).