What is the replication factor?

The replication factor (RF) determines how many copies of each partition are maintained across the cluster. With RF=3, every partition has 3 copies — one leader and two followers on separate brokers. A higher RF improves fault tolerance (RF=3 tolerates 1 broker failure; RF=5 tolerates 2) but uses more disk and network. The standard production recommendation is RF=3 with min.insync.replicas=2.

Expected key concepts: copies, partitions, RF=3, fault tolerance, leader, followers, min.insync.replicas, disk, network