Intermediate LevelSystem Design & Architecture
What is the Raft Consensus Algorithm and how does it compare to Paxos?
❓ Interview Prompt: Explain Raft Consensus Algorithm, Leader Election, Log Replication, Safety invariants, randomized election timeouts, and comparison to Paxos.
Raft is a distributed consensus algorithm designed to be understandable and equivalent to Multi-Paxos in fault tolerance:
3 Decomposed Sub-problems:
1
Leader Election: Uses randomized election timeouts to elect a single Leader node per Term.
2
Log Replication: Leader accepts client commands, appends them to its log, and replicates log entries to Followers.
3
Safety: Log entries are committed only after being replicated to a majority quorum ($N/2 + 1$) of nodes.
Code Implementation Example
typescript
// Raft Majority Quorum Verification
export function isQuorumReplicated(ackCount: number, totalNodes: number): boolean {
const majority = Math.floor(totalNodes / 2) + 1;
return ackCount >= majority;
}💡Verifying Raft log replication majority quorum.
🎯 Interview Key Takeaway
Raft achieves distributed consensus by electing a strong leader to manage log replication across a majority quorum.
#System Design#Raft#Consensus#Paxos#Intermediate
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