Apache Accumulo vs Apache Cassandra

Apache Accumulo is a free, open-source sorted, distributed key/value store for storing and retrieving large datasets across a cluster. It uses Apache Hadoop HDFS for data storage and Apache ZooKeeper for consensus. Each key/value pair can carry a security label, so query results can be restricted according to a user’s authorizations. Accumulo Iterators can modify key/value pairs at different stages of data management. Clusters can use one or more HDFS instances, and nodes can be added or removed as stored data changes. The project says its client API follows Long Term Maintenance releases and semantic versioning, and that each release undergoes extensive testing. The software is licensed under Apache License, Version 2.0. The downloads page lists source and binary archives for versions 4.0.0-alpha-1, 3.0.0, and 2.1.6; the project identifies 4.0.0-alpha-1 as alpha and says alpha or beta releases are not production ready. General questions can go to the user mailing list, while the dev list serves contributor discussions. An interactive tour teaches the Java API through exercises and is designed for Accumulo 2.1.x or greater.

Apache Cassandra is a free, open-source NoSQL distributed database for mission-critical data and large active datasets. Its masterless architecture gives each node the same functionality. The project says read and write throughput can grow linearly as machines are added, without downtime or application interruption. Cassandra can run on premises, with one cloud provider, across multiple providers, or in a combination of those environments. It supports replication across data centers and configurable consistency levels for queries, along with CQL, transactions, and horizontal scaling. The project lists audit logging for DML, DDL, and DCL activity, and fqltool for recording and replaying production workloads. Drivers are available for Java, Go, Python, and Node.js; downloads include tarballs and packages, and installation guidance covers Debian and RPM. The ecosystem includes tools and connectors for Apache Kafka, Apache Flink, Apache Spark, and Kubernetes. The project identifies version 5.0 as the latest GA release and says it is maintained until the 8.0 release. Cassandra is self-managed, and listed third-party ecosystem projects are not supported by its community.