- To change the consistency level, modify the following
The default consistency setting for read operations is ONE. The available consistency levels include ONE, TWO, and THREE, each of which specify the total number of replica nodes that must respond to a request. The QUORUM consistency level requires a response from a majority of the replica nodes.
For example, if read consistency is ONE, Cassandra queries any one of the copies of the data and returns the data from that copy. For multiple nodes, if read consistency is QUORUM, Cassandra queries the majority of the replicas. Cassandra considers the replica with the latest time stamp as the true one and all the other copies are updated with the latest copy.
The default consistency setting for write operations is ONE.
For example, if write consistency is ONE, Cassandra acknowledges the operation when any replica updates an entry. For multiple nodes, if write consistency is QUORUM, Cassandra acknowledges an operation after the majority of the replicas update entries.
Note: Adding nodes to a Cassandra cluster does not affect the consistency level.