Improving Performance of Flash Based Key-Value Stores Using Storage Class Memory as a Volatile Memory Extension

Explore a practical solution for improving performance and reducing costs of key-value stores running on DRAM-constrained servers using Storage Class Memories (SCM). Dive into the use of Intel® Optane™ PMem 100 Series SCMs in AppDirect mode to extend RocksDB's available memory, one of Facebook's largest key-value stores. Learn about the design of a hybrid cache in RocksDB that harnesses both DRAM and SCM hierarchically, and examine performance characterizations for three major RocksDB use cases at Facebook: WhatsApp, Tectonic Metadata, and Laser. Discover how this approach achieves up to 80% improvement in throughput and 20% improvement in P95 latency over existing small DRAM single-socket platforms, while maintaining significant cost improvements over large DRAM dual-socket platforms. Gain insights from this pioneering study of the DCPMM platform in a commercial data center environment, covering topics such as data center memory requirements, high-performance storage servers, SCM characteristics, RocksDB architecture, workload analysis, hybrid cache design, evaluation methodologies, and the limitations of SCM deployments.