Synchronous replication.

also: asynchronous replication · semi-synchronous replication · sync replication · async replication

Sync: the leader waits for follower confirmation before acknowledging a write. Async: it acknowledges at once and replicates afterwards.

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Synchronous: no acknowledged write is lost if the leader dies, but every write waits for a follower.
Asynchronous: fast writes, but a leader crash can lose the last writes, and followers lag.
Semi-synchronous: wait for one follower, the rest async; a common middle ground.
The choice is the durability-versus-latency trade-off in miniature.

also: asynchronous replication · semi-synchronous replication · sync replication · async replication

Sync: the leader waits for follower confirmation before acknowledging a write. Async: it acknowledges at once and replicates afterwards.

Synchronous: no acknowledged write is lost if the leader dies, but every write waits for a follower.
Asynchronous: fast writes, but a leader crash can lose the last writes, and followers lag.
Semi-synchronous: wait for one follower, the rest async; a common middle ground.
The choice is the durability-versus-latency trade-off in miniature.