The Commit Log: How Kafka Stores Data
Learn how Kafka stores messages as an append-only commit log, how offsets and retention work, and why this design makes Kafka fast and durable.
Kafka Is a Log
At its core Kafka is a distributed, append-only commit log. Producers append to the end and data is never modified in place — that's the secret to its speed and durability.
Append-Only Writes
Every record is written sequentially to the end of a partition's log. Sequential disk writes are far faster than random ones, sustaining high throughput on cheap disks.
All lessons in this course
- What is Apache Kafka?
- Kafka Core Concepts: Brokers, Topics
- Setting Up Kafka Locally
- The Commit Log: How Kafka Stores Data