Definition - What does Apache Cassandra mean?
Techopedia explains Apache Cassandra
Cassandra uses a peer-to-peer architecture instead of the master/slave setup used in RDBMSs. There is no master server in the former like in peer-to-peer file sharing. If a master server stalls or breaks down because of numerous requests, the slave servers are rendered useless, whereas in a peer-to-peer setup, every database cluster is equal and can accept requests from any client. As a result, Cassandra has no single point of failure.