IONIA: High-Performance Replication for Modern Disk-based KV Stores

We introduce IONIA, a novel replication protocol tailored for modern SSD-based write-optimized key-value (WO-KV) stores. Unlike existing replication approaches, IONIA carefully exploits the unique characteristics of SSD-based WO-KV stores. First, it exploits their interface characteristics to defer parallel execution to the background, enabling high-throughput yet one round trip (RTT) writes. IONIA also exploits SSD-based KV-stores’ performance characteristics to scalably read at any replica without enforcing writes to all replicas, thus providing scalability without compromising write availability; further, it does so while completing most reads in 1RTT. IONIA is the first protocol to achieve these properties, and it does so through its storage-aware design. We evaluate IONIA extensively to show that it achieves the above properties under a variety of workloads.