A Case Study of Migrating RocksDB on Intel Optane Persistent Memory

The application of product-level persistent memory (PM) presents a great opportunity for key-value stores. However, PM devices differ significantly from traditional block-based storage devices such as HDD and SSD in terms of IO characteristics and approaches. To reveal the adaptability of existing persistent key-value store on PM and to explore the potential optimization space of PM-based key-value stores, we migrate one of the most widely used persistent key-value store, RocksDB, to PM device and evaluated its performance. The results show that the performance of RocksDB is limited by the traditional IO stacks optimized for fast SSDs on PM devices. We then perform further experimental analysis on the IO methods of the two main files, log and SST, in RocksDB. Based on the results, we propose a set of optimized IO configurations for each of the two files. These configurations improve read and write performance of RocksDB by up to 3× and 2×, respectively, over the default configurations on an Intel Optane Persistent Memory.