What advantage does data replication provide in Cassandra?

Data replication in Cassandra is primarily advantageous because it enhances fault tolerance and availability. By maintaining multiple copies of data across different nodes in the cluster, Cassandra ensures that if one node fails or becomes unreachable, the data can still be accessed from other nodes that hold copies of the same data. This redundancy is crucial in a distributed database system where node failures could happen, allowing the system to remain operational and accessible to users.

The replication factor can be adjusted based on the needs of the application, providing flexibility in balancing data availability against storage efficiency. This design not only helps in quickly recovering data but also allows the database to handle load by directing read operations to different nodes, thereby increasing overall system resilience.

While data replication might have some impact on write operations by allowing immediate consistency across replicas and potentially speeding them up for certain configurations, the primary and most notable benefit is indeed the improved availability and fault tolerance, which is essential for maintaining uninterrupted service.