Crail-KV: A High-Performance Distributed Key-Value Store Leveraging Native KV-SSDs over NVMe-oF

A Key-Value SSD (KV-SSD) is a new type of storage device that natively exposes a key-value interface. In this paper, we leverage KV-SSDs to develop new techniques to remove unnecessary layers of indirection traditionally imposed by block devices on distributed storage systems. Specifically, we extend the Crail distributed system [1] to leverage the KV-SSD's native key-value interface exposing it directly to clients through the NVMe-oF protocol. This architectural change simplifies key-value metadata management, as the metadata manager need only track key-value tuples rather than files comprised of blocks. These changes enable fewer RPCs and require less memory for metadata management, resulting in a performance improvement of up to 5x.