Telepathy: A Lightweight Silent Data Access Protocol for NVRAM+RDMA Enabled Distributed Storage

Recent developments in non-volatile memory and networking technologies raise new challenges and opportunities for architecting storage systems. In this paper we propose Telepathy, a lightweight data access protocol for NVRAM+RDMA-based distributed storage systems. Telepathy is a fully distributed protocol whose I/O writes can be coordinated by any server node, and I/O reads can be served by any of the replicas. Telepathy guarantees strongly-consistent reads while providing high I/O concurrency. Hybrid RDMA operations are used to transmit data directly and efficiently to the NVRAM of target servers. The correctness of Telepathy is verified with a formal proof of consistency, and its performance is validated with YCSB benchmarks on the Chameleon cluster. Telepathy can achieve low I/O latencies and high throughput, with low CPU utilization.