Kafka topics are divided into partitions for parallel processing. Each partition is an ordered, immutable log.
Key properties:
- Messages within a partition maintain FIFO order
- Partitions distributed across brokers
- Each partition has one leader and N replicas
Parallelism:
- More partitions = more parallel consumers
- Cannot have more active consumers than partitions
- Typical: - partitions per topic to start
Partitions cannot be decreased after creation. Plan for growth.