Tech Talk - Raft, In Search of an Understandable Consensus Algorithm by Diego Ongaro

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Published 2014-10-06

Raft is a consensus algorithm for managing a replicated log. It produces a result equivalent to (multi-)Paxos, and it is as efficient as Paxos, but its structure is different from Paxos; this makes Raft more understandable than Paxos and also provides a better foundation for building practical systems. In order to enhance understandability, Raft separates the key elements of consensus, such as leader election, log replication, and safety, and it enforces a stronger degree of coherency to reduce the number of states that must be considered. Results from a user study demonstrate that Raft is easier for students to learn than Paxos. Raft also includes a new mechanism for changing the cluster membership, which uses overlapping majorities to guarantee safety.

All Comments (11)

@hedgehog_fox 5 years ago

The animation is brilliant!
@donha475 4 years ago

Wow. Really great explanation. Bravo! :)
@theMou 9 years ago

thank you.
@robertoacosta5542 2 years ago

Hi, I still don't understand how honey badger works and if you know how its performance is compared to raft or beat (although I understand that beat has better performance than honey badger since it is based on it, therefore it improves it) if you could Help with this would be greatly appreciated.
@enthusiasticgeek 9 years ago

While the election is taking place between the servers, are clients not connected to any server? If clients are disconnected to begin with, how do they know (a) Election for term is over (b) leader to connect to for operation? They have to connect to some server (leader or not) first in order to receive messages. Isn't that correct?
@titancryptograph6523 3 years ago

Check the Hedera Consensus Service.
@enthusiasticgeek 9 years ago

I have read these slide. As a beginner, I am not clear about one thing. Can servers join the cluster dynamically or are they static prior to commencing cluster operation. Meaning if there are already 5 servers, 1 being the leader rest 4 servers being the followers, can 6th server join in the cluster? And if it joins (assuming dynamic operation) - how are other servers made aware of it's presence (maybe even before the election for leader ship)? e.g. do they ping every ip on the subnet (remember these could be on a different network or worst on the cloud). Can someone explain this clearly?
@JeffChentingwei628 2 years ago

10:43 LOL
@DawcaWspomnien 9 years ago

Bylem na tej stronie i nie ma slawnych polskich postaci jak np Józef Piłsudski ,Jan Paweł II (1920-2005);Ernest Malinowski Maria Curie-Skłodowska Kazimierz Wielki (1310-1370) i wiele innych ktore sa duma dla Polakow .I chcieli by byc follow
@haralc 3 years ago

why some tech geeks talk like they're drunk???