hyperledger/sawtooth-raft-engine repository overview

Sawtooth Raft is a consensus engine for Hyperledger Sawtooth based on the crash-fault-tolerant consensus algorithm Raft. Sawtooth Raft is built on top of raft-rs, the Rust implementation of Raft used by TiKV.

Sawtooth Raft has several major differences from the PoET and dev mode consensus engines:

• Leader-based consensus: The Raft algorithm defines an election process where a leader is established and recognized by all followers. Only one node—the leader—publishes blocks, which are then validated and agreed on by the other nodes in the network—the followers.

• Non-forking: No forks arise on a Raft network because only one node can publish blocks. Fork resolution is not required, which reduces the overhead associated with block management and lends itself to increased performance.

• Fixed membership: Raft requires that a majority of nodes agree on all progress that is made. To ensure safety by preventing invalid node configurations, Sawtooth Raft does not support open membership. The population of nodes is fixed unless changed by an administrator.

• Best for small networks: Raft requires exchanging messages between all nodes to reach consensus for each block, and the leader must wait for a majority of nodes to agree on a new entry before it can be committed. The number of messages increases exponentially with the size of the network, which make large networks impractical.

• Not Byzantine fault tolerant: The Raft algorithm was designed to be crash fault tolerant—it can continue to make progress as long as a majority of its nodes are available. However, Raft only guarantees safety and availability under non-Byzantine conditions, which makes it ill-suited for networks that require Byzantine fault tolerance.

Learn more at https://sawtooth.hyperledger.org/docs/raft/nightly/master/⁠