What is a distributed log and how does it power modern data systems like Kafka?

A distributed log is an append-only, ordered sequence of records stored across multiple nodes.

A distributed log provides a durable, immutable event store where data is appended sequentially and consumers read at their own pace. Systems like Apache Kafka implement this using partitioned logs replicated across brokers. This architecture decouples producers and consumers, enabling replayability, fault tolerance, and scalability. Unlike traditional queues, logs preserve history and allow multiple independent consumers.