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Questions tagged [paxos]

Paxos is a family of protocols for a network of unreliable processors to agree on a result.

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Why does Paxos ensure that consensus is reached and does not change?

I have been reading about single-decree Paxos (primarily looking at Paxos Made Simple) yet am confused about if a consensus among Acceptors is guaranteed to not change after being reached. According to James Aspnes's notes, So now we suppose that…
kyou
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How to implement Byzantine Single-decree Paxos?

I have implemented Single-decree Paxos, and have shown it not to fail in a Monte Carlo network simulator. I followed "Paxos Made Simple" http://lamport.azurewebsites.net/pubs/paxos-simple.pdf I have read: Castro, Miguel; Liskov, Barbara (February…
fadedbee
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Isabelle proof of correctness for Raft / Paxos algorithm

Can Isabelle help to prove the correctness of the Raft or Paxos consensus algorithm? Is there a formal proof somewhere?
Nathan B
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How does Basic Paxos proposer know when to increment roundId / proposal number

Looking at the screenshot from this video, around 27:20 https://www.youtube.com/watch?v=JEpsBg0AO6o When server S5 sends out the prepare RPC, it uses the roundId (proposal number) 4 and server number 5 (hence 4.5) as well as value "Y". But how does…
Max
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In Paxos, assume that acceptors do not change their vote, can it reach a livelock?

So, I’m studying Paxos and the Professor made this question: Assume that acceptors do not change their vote. In other words, if they vote for value v in round i, they will not send learn messages with value different from v in larger rounds. Show…
eddie
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paxos: why do ids have to increase monotonically?

This is pseudocode for prepare stage: Is this ID bigger than any round I have previously received? If yes store the ID number, max_id = ID respond with a PROMISE message If no do not respond (or respond with a "fail"…
nz_21
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paxos algorithm - how does the propose stage work?

I am looking at the pseudocode for the PROPOSE stage of the paxos algorithm: https://www.cs.rutgers.edu/~pxk/417/notes/paxos.html did I receive PROMISE responses from a majority of acceptors? if yes do any responses contain accepted values (from…
nz_21
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Do proposal numbers need to be unique in Paxos?

What can happen if two proposals are issued with the same ProposalId? It shouldn't create any problem if they have the same value. But what about different values? I can work out a scenario where it risks liveness at the time of failure, but would…
narengi
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How a distributed storage system like Raft filter duplicate requests even after client session expiration

I am trying to understand how a distributed storage system built on Raft filter duplicate requests even after client session expiration. I have gone through the Raft dissertation chapter 6.3 which talks about how LogCabin (which is a distributed…
Yathish Manjunath
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Mencius and AllConcur Consensus Algorithms

Just wanted to ask if anyone has had any thoughts on the similarities and differences between the Mencius and AllConcur consensus protocols? At first glance these algorithms are presented very differently but I have a gut feeling that there are many…
Michael Davis
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what decides the roles in Paxos?

When people describe Paxos, they always assume that there are already some proposers in the cluster. But where are the proposers from, or what decides which processes to be proposers?
Lu Liu
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Can paxos consensus be followed in blockchain

Paxos is a fault tolerant distributed consensus algorithm. Are there any blockchain frameworks which follows paxos algorithm for adding blocks to the blockchain.
Satya Narayana
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Paxos: How are proposers, accepters and learners selected?

I want to elect a leader from a number of identical processes. All the explanations of Paxos say that some processes are Proposers, some are Voters and some are Accepters. Do I need to assign these roles to my processes when I launch them? What if…
gruszczy
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Why paxos in mysql group replication jump prepare phase？

I see such code segment in proposer_task(xcom_base.c) if(threephase || ep->p->force_delivery){ push_msg_3p(ep->site, ep->p, ep->prepare_msg, ep->msgno, normal); }else{ push_msg_2p(ep->site, ep->p); } the threepahse is int const threephase =…
jfxu
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Consensus algorithm for Node.js

I'm trying to implement a collaborative canvas in which many people can draw free-handly or with specific shape tools. Server has been developed in Node.js and client with Angular1-js (and I am pretty new to them both). I must use a consensus…
JackLametta
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