Apache Cassandra is described as 'has become the leading NoSQL platform driving many of today's modern business applications by offering continuous availability, high scalability and performance, strong security, and operational simplicity while lowering the overall cost of ownership' and is a relational database in the development category. There are more than 25 alternatives to Apache Cassandra for a variety of platforms, including Linux, Windows, Mac, BSD and Online / Web-based. The best alternative is PostgreSQL, which is both free and Open Source. Other great apps like Apache Cassandra are MongoDB, MySQL Community Edition, MariaDB and Redis.
PostgreSQL is a powerful, open source object-relational database system. It has more than 15 years of active development and a proven architecture that has earned it a strong reputation for reliability, data integrity, and correctness.
PostgreSQL vs Apache Cassandra opinions
This alternative is disputed. PostgreSQL is still a legitimate alternative to Apache Cassandra, but it might have issues that some users think are important.
Cassandra is a NoSQL database, this one is a SQL database.
Redis™ (REmote DIctionary Server) is an open-source, networked, in-memory, key-value data store with optional durability. It is often referred to as a data structure server since keys can contain strings, hashes, lists, sets and sorted sets.
Redis vs Apache Cassandra opinions
pros, cons and recent comments
Cassandra is a persistent database, Redis is meant as a distributed in-memory caching system
SQL Server delivers on Microsoft’s Data Platform vision by helping your organization manage your data by enabling you to store data from structured, semi-structured, and unstructured documents within the database.
Apache CouchDB is a distributed, fault-tolerant and schema-free document-oriented database accessible via a RESTful HTTP / JSON API. It includes incremental map / reduce mechanics for queries and keeps data safe with an append-only datastore.
Cockroach is a distributed key/value datastore which supports ACID transactional semantics and versioned values as first-class features. The primary design goal is global consistency and survivability, hence the name.