RocksDB vs RonDB

RocksDB is an embeddable, persistent key-value store for applications that need fast storage. It stores keys and values as arbitrary byte arrays, with ordering determined by a comparator chosen by the user. Its log-structured merge design allows configuration of tradeoffs among write, read, and space amplification, and the project describes it as optimized for low-latency storage on flash drives and high-speed disks. The C++ library supports opening and closing databases, reads and writes, merging, and compaction filters. Described uses include database storage engines, application data caches, and embedded workloads. Multi-threaded compactions support databases holding multiple terabytes; the project describes an audience of application servers storing up to a few terabytes on local or remote systems. RocksDB also has a Java wrapper, RocksJava, with artifacts published through Maven. It is free and open source under either GPLv2 or Apache 2.0, at the user's choice. Building requires GCC 11 or later or Clang 10 or later for C++20 support; values must be smaller than 4 GB.

RonDB is an open-source distributed storage engine for real-time applications and a fork of MySQL NDB Cluster. Its shared-nothing design supports up to 1 PiB of storage, with online horizontal and vertical scaling for storage and MySQL-server compute. Applications can use the MySQL Server API for SQL-compatible access and parallel queries. ACID transactions are provided through MySQL-server support; in-memory data is persisted using REDO logs and checkpoints.

RonDB describes its performance aims as low latency, high availability, high throughput, and scalable storage. It supports AI application storage integrated with Spark and Kafka, while Rondis implements a Redis server using RonDB storage and the Redis wire protocol. Deployment options include local testing, Docker, cloud deployments using your own AWS, Azure, or GCP credentials, and on-premises deployment by inquiry. Replication can be synchronous active-active across availability zones or asynchronous across regions with conflict resolution. RonDB is used as the online feature-store database for machine-learning applications in Hopsworks. The serverless plan through Hopsworks is free, with quotas on Feature Groups and memory usage.