The Paxos algorithm is a widely adopted approach to reaching agreement in unreliable asynchronous distributed systems. Since its development in 1998, Paxos has been extensively researched, taught and built upon by systems such as Chubby, Zookeeper and Raft. At its foundation, Paxos uses two phases, each requiring agreement from a quorum of participants to reliably reach consensus. This lecture will introduce Flexible Paxos, the simple yet powerful result that each of the phases of Paxos may use non-intersecting quorums. The result means that majorities are no longer the only practical quorum system for Paxos, opening the door to a new breed of performant, scalable and resilient consensus algorithms. This lecture will demonstrate how we are able to test this result with only simple modifications to the existing Paxos TLA+ specification.
See more on this video at www.microsoft.com/en-us/research/video/flexible-paxos/