consensus

Heidi Howard's Reactive Summit 2018 talk on generalizing Paxos by weakening its original requirements. She shows Paxos is one point on a broad spectrum of consensus approaches.

David Mazieres presents the Stellar Consensus Protocol at Google, introducing federated Byzantine agreement. The model lets participants choose whom to trust rather than assuming fixed membership.

John Ousterhout's slides-and-voiceover lecture on Paxos, made for the Raft user study comparing how students learn Raft and Paxos. It is a full introduction to the Paxos consensus algorithm.

An AWS re:Invent 2014 talk on the core distributed systems primitives behind AWS and Amazon.com, such as consensus, key-value stores and transactional logging. It describes how AWS builds large services from a few common building blocks.

The opening lecture of MIT 6.824 Distributed Systems (Spring 2020), introducing the course and core challenges of distributed systems. It begins a playlist that goes on to cover Raft and other consensus papers in Go.

John Ousterhout lectures on the Raft consensus algorithm, made for the Raft user study comparing how students learn Raft and Paxos. It covers leader election and log repair.

The first lecture in Martin Kleppmann's 8-lecture distributed systems series from the University of Cambridge undergraduate course. It introduces the subject, and accompanying lecture notes are available.

Sasa Juric explains what makes Erlang and Elixir suited to server-side systems, focusing on the BEAM concurrency model rather than syntax or ecosystem. He demonstrates processes, supervision, and fault tolerance.

Will Wilson of FoundationDB explains how the team tested their distributed database using deterministic simulation. By running the whole system in a simulator with injected faults and reproducible seeds, they could find rare concurrency and network bugs.

Rick Reed of WhatsApp explains at Erlang Factory 2014 how the service scaled to billions of messages with a very small engineering team. He covers the FreeBSD and Erlang stack, Mnesia usage, server counts and bottleneck work.

Martin Kleppmann argues that databases are global shared mutable state and proposes treating them as an ever-growing log of immutable facts. Derived data such as caches, indexes and views is then built by stream processors like Apache Samza. The talk draws on Kafka and LinkedIn's experience with commit logs.

Rich Hickey's 2013 talk applies language-design thinking to whole systems, covering names, queues, data, failure, and the interfaces between programs. It ends with a call to action for building systems holistically.

Rob Pike's Google I/O 2012 talk shows how goroutines and channels solve tricky concurrency problems with simple Go code. It features a playful goroutine demo with gophers passing messages and a search engine example.

Martin Kleppmann's GOTO Berlin 2016 talk on how collaborative editors, offline apps, and multi-datacenter databases handle concurrent updates. It covers conflict resolution approaches including operational transformation and CRDTs, with a worked look at text CRDTs.

Paul Chiusano's Strange Loop 2019 talk introduces Unison, an open-source functional language for distributed, elastic systems. It covers content-addressed code identified by hashes of the syntax tree, a codebase manager, and algebraic effects called abilities.

A standing whiteboard conversation at Lang.NEXT 2012 among Carl Hewitt, Erik Meijer and Clemens Szyperski about the actor model. Hewitt, who originated the model, explains its foundations.

A 2007 Google Tech Talk in which Cliff Click of Azul Systems presents a lock-free concurrent hash table that scales to 768 CPUs. He explains why it is correct by reasoning in a different way than usual happens-before and memory-order arguments.

Peter Alvaro's Strange Loop 2015 talk argues that query languages let you state what you mean, and applies that to distributed programming. It covers Datalog, Dedalus and the Bloom lineage for reasoning about distributed systems.

Daniel Azuma's ElixirConf 2018 talk on whether Docker and OTP conflict. He shows they can coexist and uses Horde and DeltaCrdt, with a live tank-game demo, to keep state alive across container kills.

Bryan Hunter's GigCityElixir 2023 talk on HCA Healthcare's Waterpark system, built on Elixir/Erlang. It describes how the architecture is distributed and fault-tolerant, with a multi-datacenter cluster and runtime code swapping.

Leslie Lamport argues that programmers, like architects, should write rigorous specifications before coding, especially for concurrent and distributed systems. The talk introduces the case for writing specs (the TLA+ mindset) as a way of thinking above the code.

Zach Tellman's Clojure West talk covers the basics of queueing theory and its practical use in systems, including backpressure, how queues break down under load, and pitfalls of naive core.async use.

James Hamilton's Tuesday Night Live keynote at AWS re:Invent 2016, touring AWS infrastructure at scale including networking, power and custom silicon. It also features NASA JPL's Tom Soderstrom.

Dan Robinson, then CTO of Heap, explains how Heap runs its product analytics backend on PostgreSQL and CitusDB. It covers conversion funnels, retention and cohort queries across tens of billions of events and 50 TB of data, plus Postgres and Kafka together and the indexing strategy.

Dropbox engineer Kevin Modzelewski gives a Stanford colloquium on Dropbox's history and the technical problems it faced scaling, including detailed database schema decisions.

A 2018 GDC panel where Raph Koster, Starr Long, Richard Garriott and Rich Vogel look back on what went right and wrong building and running Ultima Online. They share candid stories from the early days, including player behavior and server architecture.

Bungie's David Aldridge explains the networking programming behind Halo: Reach in a 2011 GDC session. It covers how gameplay stays in sync online, including forecasting and state reconciliation.

Will Wilson explains autonomous testing: using deterministic simulation and fuzzing, building on FoundationDB's approach, to test software continuously. It sets out the ideas behind his later company Antithesis.

Dr. Richard Cook, a physician and patient safety researcher, presents his ideas on how complex systems fail, at Velocity 2012. He argues for designing for resiliency rather than trying to exhaustively handle every failure mode.

James Long's dotJS 2019 talk on how CRDTs enable local-first apps and how simple they can be to implement. He shows how to use them to build robust offline-capable frontends.

Andrew Tanenbaum's FOSDEM 2010 talk on MINIX 3, a microkernel OS built for high reliability and security. It shows how the system detects and recovers from device driver crashes, and addresses microkernel performance concerns.

Jeff Dean of Google describes his experiences building Google's systems and how its infrastructure evolved over time. The Stanford talk covers search, scaling tipping points and lessons from building large-scale software.

A short Ericsson film demoing Erlang, showing concurrent processes, debugging tools, and hot code reloading, including crashing parts of a running system while calls continue.

Martin Kleppmann's QCon London 2018 talk on keeping data consistent in distributed systems without a central leader. It surveys CRDT algorithms for syncing devices and collaborative editing over peer-to-peer networks.

Jon Moore's Strange Loop 2017 talk argues that rate limiting is the wrong tool for protecting services from noisy clients. He proposes concurrency-based capacity management and quotas instead.

A panel with Tony Hoare, Joe Armstrong and Carl Hewitt, hosted by Francesco Cesarini, on the history and future of concurrency. The three creators of CSP, Erlang and the actor model discuss their differing approaches.

Sasa Juric's EMPEX talk demonstrates Elixir and Erlang's process model and what makes the BEAM runtime distinctive, such as fault-tolerant parallelism by design.

Martin Kleppmann surveys current research on CRDTs, the algorithms for merging concurrent edits across offline replicas. He covers the hard parts such as rich text, moves and merge results that are technically correct but poor.

Peter Rizun and Andrew Stone present results of tests running 1 GB blocks on a Bitcoin test network at Scaling Bitcoin Stanford. The talk argues for big-block scaling and discusses its consequences.

Neil Fraser of Google presents Differential Synchronization, the algorithm behind MobWrite, for keeping multiple copies of a document in sync in real time. The talk argues the approach is robust, convergent and efficient.