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LibraryConsensus2014Design paperCorpus record

In Search of an Understandable Consensus Algorithm

Raft. Diego Ongaro and John Ousterhout.

A strong leader accepts entries, replicates them in order, and commits only when a majority of the current term has stored them.

A reading of the public document. Not a copy of it, and not a claim about a later network that reused the name.

Most 'our own consensus' pitches are a broken Raft. Ask about the election restriction and the commit rule for entries from an older term.
Evidence
Primary paper
Re-measured
No
Assumptions
3
Records linked
3

Code

Source, repository, and what is actually hosted

  • Raft paperhttps://raft.github.io/raft.pdf
  • The source URL is not a GitHub repository. No code remote is invented.
  • Full text is not mirrored. Public availability is not a licence to copy the file onto this site.
  • Add to a reading list

01 Claim ledger

What the paper is allowed to say

Each row is a sentence already in the study. The status is the same on every row: a model claim, not a live measurement.

  1. Claim 01 · Paper model

    The defect

    Paxos was correct and routinely mis-implemented. Raft separates leader election, log replication and safety so a reader can see which rule prevents a split brain.

  2. Claim 02 · Paper model

    The rule

    A strong leader accepts entries, replicates them in order, and commits only when a majority of the current term has stored them.

  3. Claim 03 · Paper model

    How it is put together

    Terms are numbered epochs. At most one leader per term. A follower rejects a log that does not continue its own. A candidate must have an up-to-date log to win an election.

  4. Claim 04 · Paper model

    Where the claim stops

    Raft assumes a known set, or an explicit membership change.

02 Three cuts

Observation, model, falsifier

A desk does not stop at the summary. Each claim is cut three ways, using only this study's own assumptions and checks. Nothing here is a new figure.

  1. 01 The defect

    Observation

    What the study says

    Paxos was correct and routinely mis-implemented. Raft separates leader election, log replication and safety so a reader can see which rule prevents a split brain.

    Model

    What has to hold

    It is not Byzantine. A malicious leader can lie to clients.

    Falsifier

    What would retire it

    Can a candidate with a stale log win?

  2. 02 The rule

    Observation

    What the study says

    A strong leader accepts entries, replicates them in order, and commits only when a majority of the current term has stored them.

    Model

    What has to hold

    It is not Byzantine. A malicious leader can lie to clients.

    Falsifier

    What would retire it

    Is commit delayed for entries from previous terms?

  3. 03 How it is put together

    Observation

    What the study says

    Terms are numbered epochs. At most one leader per term. A follower rejects a log that does not continue its own. A candidate must have an up-to-date log to win an election.

    Model

    What has to hold

    It is not Byzantine. A malicious leader can lie to clients.

    Falsifier

    What would retire it

    Can a candidate with a stale log win?

  4. 04 Where the claim stops

    Observation

    What the study says

    Raft assumes a known set, or an explicit membership change.

    Model

    What has to hold

    Raft assumes a known set, or an explicit membership change.

    Falsifier

    What would retire it

    How does membership change avoid two majorities?

03 Sequence

One action, as an operating tape

  1. 01Heartbeats keep the leader. Their absence starts an election.
  2. 02The leader appends a command and waits for a majority of matching stores.
  3. 03A new leader forces followers to match its log before taking new commands.
  4. 04Can a candidate with a stale log win?

04 Load-bearing

The argument, and where a pitch drops it

  1. Why it is still on the desk

    The cut

    Most 'our own consensus' pitches are a broken Raft. Ask about the election restriction and the commit rule for entries from an older term.

    Why it carries weight

    If this cut is skipped, the paper's name is being used without the mechanism that makes the name mean anything.

    Where it is dropped

    A later client, parameter or reward formula is a different object from this paragraph.

  2. After the text

    The cut

    etcd, Consul and many orderers ship Raft. A blockchain that needs Byzantine faults has left this paper.

    Why it carries weight

    If this cut is skipped, the paper's name is being used without the mechanism that makes the name mean anything.

    Where it is dropped

    It is not Byzantine. A malicious leader can lie to clients.

05 Register

What has to be true

  • Model · Not re-measured

    Raft assumes a known set, or an explicit membership change.

  • Stake and threshold · Not re-measured

    It is not Byzantine. A malicious leader can lie to clients.

  • Cryptography · Not re-measured

    Randomised timeouts are a liveness trick, not a safety proof.

06 Divergence

What happened after the paper

etcd, Consul and many orderers ship Raft. A blockchain that needs Byzantine faults has left this paper.

A later client, parameter set, or reward formula is a different object. Cite this paper for the mechanism. Cite a primary release for the network. This desk has not re-run the proof.

07 Pre-mortem

What to check before you use the idea

  4. 0 of 3 marked on this browser. A mark is a reading note, not a pass, a rating, or a recommendation.

08 Anatomy

The paper, in the order a builder needs

The problem it names

Paxos was correct and routinely mis-implemented. Raft separates leader election, log replication and safety so a reader can see which rule prevents a split brain.

What the design proposes

  • Terms are numbered epochs. At most one leader per term.
  • A follower rejects a log that does not continue its own.
  • A candidate must have an up-to-date log to win an election.

How the mechanism is specified

  • Heartbeats keep the leader. Their absence starts an election.
  • The leader appends a command and waits for a majority of matching stores.
  • A new leader forces followers to match its log before taking new commands.

What this page does not treat as proven

  • Raft assumes a known set, or an explicit membership change.
  • It is not Byzantine. A malicious leader can lie to clients.
  • Randomised timeouts are a liveness trick, not a safety proof.

Why the desk still reads it

Most 'our own consensus' pitches are a broken Raft. Ask about the election restriction and the commit rule for entries from an older term.

09 Lexicon

Terms, opened into the record

Term
A numbered epoch with at most one leader.
Log matching
If two logs share an index and term, they share every earlier entry.

10 Repository

Every linked record on this page

Underlined words open a page that already exists: a concept, a protocol profile, a failure record, or another paper. If a word is not underlined, this desk does not have a record for it.

This is Blockchain Lab's reading of a public design paper. It is not the paper, not a copy of it, and not an offer of tokens, equity, custody or a partnership. Later network behaviour can diverge from the text. Nothing here is investment, legal or technical advice.

Research status: Design paper. Last reviewed: 1 October 2026. This is a reading of a public paper, not investment, legal or security advice.