Track 2 · Building Blocks
Replication and Leader Election
Keep copies of your data on more than one machine, let exactly one machine take the writes, and have a safe way to pick a new one when it dies. This page covers how the copies stay in step, how Raft picks a leader, and why a stale leader is still dangerous.
Guide22 min read
On this page
- The night the primary went quiet
- The simple version
- How single-leader replication works
- Failure detection: how do you know the leader is dead?
- Raft in plain words
- Split-brain, and what Raft really guarantees
- Failover managers that are not Raft themselves
- What the real systems do
- Other ways to replicate
- The war room: flapping failovers at Tatkal time
- How to choose