Replica Set
In plain terms
A group of database nodes maintaining the same data.
Going deeper
A replica set keeps multiple copies of data in sync, providing redundancy and automatic failover if the primary fails. It ensures data availability.
Under the hood
One primary handles writes, secondaries replicate; elections promote a new primary on failure (e.g., MongoDB).
Examples
MongoDB, high availability, failover, data redundancy, read scaling.
Think of it like...
Like a team keeping identical copies of records so work continues if one keeper is lost.