Paxos: The Classical Consensus Protocol
Understand Leslie Lamport's Paxos: Proposers, Acceptors, Learners, Phase 1 (Prepare/Promise), Phase 2 (Accept/Accepted), and Multi-Paxos.
01.1. The History & Formal Roles of Paxos
Introduced by Turing Award winner Leslie Lamport in his 1998 paper "The Part-Time Parliament", Paxos was the world's first mathematically proven protocol for achieving distributed consensus over an asynchronous, unreliable network with crash-recovery failures.
Paxos categorizes cluster nodes into three logical roles (which often run inside the same physical process):
- Proposers: Receive transaction proposals from clients, advocate for their acceptance by assigning monotonically increasing proposal numbers (
N), and drive the voting rounds. - Acceptors: The voting majority quorum. They store promises and accepted values in persistent disk storage (WAL) and cast votes.
- Learners: Observer nodes that watch for majority decisions, execute the committed transactions against local state machines, and respond to clients.
Basic Paxos 2-Phase Protocol Flow 📜
Basic Paxos 2-Phase Protocol Flow 📜
Prepare/Promise phase followed by Accept/Accepted phase.
Unlock Topic #83: Paxos: The Classical Consensus Protocol
You are viewing a preview. The full in-depth engineering deep dive, interactive simulators, architecture flowcharts, and self-assessment quizzes for this topic are available with Pro or Lifetime Access.
Failure modes, high-throughput bottlenecks, and real FAANG implementation decisions.
Interactive system topology diagrams, live parameter simulators, and downloadable SVG charts.
Staff-level multiple-choice quiz questions with instant feedback and answer explanations.
Firebase Google authentication automatically syncs your completed topics and quiz scores.
How clear and staff-actionable was this system breakdown?