Backend & systems·Consistency and replication
the primary stopped answering and something promoted a replica, and now you find out how much of the last few seconds you lost.
Failover
Also calledpromotion, automatic failover
Promoting a replica to leader when the current leader is deemed dead. Under asynchronous replication it loses any unreplicated writes; under synchronous it may refuse to proceed. The hard part is the deeming: too eager and you failover on a network blip, too slow and the outage is the timeout.