Hamband: RDMA Replicated Data Types

PLDI'22 (ACM SIGPLAN Conference on Programming Language Design and Implementation)

Farzin Houshmand, Javad Saberlatibari, Mohsen Lesani


Data centers are increasingly equipped with RDMAs. These network interfaces mark the advent of a new distributed system model where a node can directly access the remote memory of another. They have enabled microsecond-scale replicated services. The underlying replication protocols of these systems execute all operations under strong consistency. However, strong consistency can hinder response time and availability, and recent replication models have turned to a hybrid of strong and relaxed consistency. This paper presents RDMA replicated data types, the first hybrid replicated data types for the RDMA network model. It presents a novel operational semantics for these types that considers three distinct categories of methods and captures their re- quired coordination, and formally proves that they preserve convergence and integrity. It implements these semantics in a system called Hamband that leverages direct remote accesses to efficiently implement the required coordination protocols. The empirical evaluation shows that Hamband outperforms the throughput of existing message-based and SMR-based implementations by more than 4x.