{ inercia }

Paxos Made Moderately Complex

For anybody who has ever tried to implement it, Paxos is by no means a simple protocol, even though it is based on relatively simple invariants. This paper provides imperative pseudo-code for the full Paxos (or Multi-Paxos) protocol without shying away from discussing various implementation details. The initial description avoids optimizations that complicate comprehension. Next we discuss liveness, and list various optimizations that make the protocol practical.