What is Cassandra's replication strategy?

Cassandra replication stores multiple copies of each partition across different nodes for fault tolerance. Configure per keyspace: CREATE KEYSPACE my_app WITH replication = {'class': 'NetworkTopologyStrategy', 'dc1': 3, 'dc2': 2};. SimpleStrategy: places replicas on the next N nodes in the ring (clockwise). Only use for single datacenter setups or testing. NetworkTopologyStrategy: places replicas in specific datacenters with rack awareness. The production choice for multi-DC deployments. Specify replicas per datacenter. Replication factor (RF): how many copies of each partition. RF=3 means 3 copies across 3 nodes (with NetworkTopologyStrategy, spread across racks). With RF=3: you can lose 1 node and still read/write with QUORUM consistency. Consistency level interaction: for strong consistency, reads + writes must overlap: RF=3 with QUORUM (2 nodes) means writes go to 2 nodes and reads come from 2 nodes — guaranteed to see the latest write.