Cassandra is a popular wide-row, column-family store [[NoSQL]] database. Cassandra is free, open source originally developed by Facebook. Cassandra is massively scalable, designed for high performance, high scalability and high availability. DataStax is a leading vendor for Cassandra. Cassandra is a peer-to-peer fully distributed system. Data are replicated and sharded across multiple nodes in a cluster. Cassandra distributes data and query workload based on the available resources. # installation # query language Cassandra Query Language (CQL) is the query language for Cassandra. CQL is very similar to [[SQL]].