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A replica set in MongoDB is a group of mongod processes that maintain the same data set. Replica sets provide redundancy and high availability, and are the basis for all production deployments. This section introduces replication in MongoDB as well as the components and architecture of replica sets. The section also provides tutorials for common tasks related to replica sets.

You can download this section in PDF form as Replication and MongoDB.

Replication Introduction
An introduction to replica sets, their behavior, operation, and use.
Replication Concepts

The core documentation of replica set operations, configurations, architectures and behaviors.

Replica Set Members
Introduces the components of replica sets.
Replica Set Deployment Architectures
Introduces architectural considerations related to replica sets deployment planning.
Replica Set High Availability
Presents the details of the automatic failover and recovery process with replica sets.
Replica Set Read and Write Semantics
Presents the semantics for targeting read and write operations to the replica set, with an awareness of location and set configuration.
Replica Set Tutorials
Tutorials for common tasks related to the use and maintenance of replica sets.
Replication Reference
Reference for functions and operations related to replica sets.