Apache Kafka has shown that the log is a powerful abstraction for data-intensive applications. It can play a key role in managing data and distributing it across the enterprise efficiently. Vital to any data plane is not just performance, but availability and scalability. In this session, we examine what a distributed log is, how it works, and how it can achieve these goals. Specifically, we'll discuss lessons learned while building NATS Streaming, a reliable messaging layer built on NATS that provides similar semantics. We'll cover core components like leader election, data replication, log persistence, and message delivery. Come learn about distributed systems!