Thanks for the question. YugabyteDB currently relies on SSDs for persistence. Persistent memory is an area of exploration for the future. Also note it relies on a significantly customized RocksDB version which is no longer kept in sync with upstream RocksDB. This has been true since the early days of the project. This post goes into some of the detail around the RocksDB-related enhancements if you are interested. Enhancing RocksDB for Speed and Scale | YugabyteDB