Consistent hashing is a type of hashing algorithm that maps data to variable length and provides an effective pattern for mapping keys to particular nodes in distributed database systems like Apache Cassandra or DataStax Enterprise. This method minimizes reorganization when nodes are added or removed, with partitions based on partition keys. The partition key should not be confused with a primary key; it is more like a unique identifier controlled by the system that makes up part of a composite key. In a four-node cluster, data distribution occurs according to the value of the partition key and the range each node is responsible for.