Kafka replikerer partitioner på tværs af flere brokere for holdbarhed og tilgængelighed — hver partition har en leader og follower-replikaer. Hvis en broker fejler, overtager en follower. At forstå replikering er nøglen til Kafkas fejltolerance.
Hvordan replikering fungerer
Each PARTITION is replicated across multiple brokers (REPLICATION FACTOR copies, e.g. 3):
→ LEADER replica → handles all reads and writes for the partition
→ FOLLOWER replicas → copy (replicate) the leader's data, staying in sync
→ producers/consumers interact with the LEADER; followers are backups
→ if the leader's broker FAILS → a follower is promoted to leader (failover) → no data loss,
continued availability
