Replica Set
Noun · Development
Definitions
A group of redundant instances maintaining the same data or workload — in MongoDB, a cluster of mongod processes with one primary and multiple secondaries that automatically elect a new primary on failure; in Kubernetes, a controller that ensures a specified number of identical pod replicas are running at all times.
In plain English: A group of identical copies of a database or service that work together so if one fails, the others automatically take over.
Example: "The MongoDB replica set elected a new primary within 10 seconds of the old one going down — the app didn't even notice."