Kafka Guarantees

  • Messages are appended to a topic-partition in the order they are sent
  • Consumers read messages in the order stored in a topic-partition
  • With a replication factor of N, producers and consumers can tolerate upto N-1 brokers being down
  • This is why a replicaton factor of 3 is a good idea:
    • Allows for one broker to be taken down for maintenance
    • Allows for another broker to be taken down unexpectedly
  • As long as the number of partitions remains constant for a topic (no new partitions), the same key will always go to the same partition