Replica set configuration basics in MongoDB - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a MongoDB replica set?

A MongoDB replica set is a group of mongod processes that maintain the same data set, providing redundancy and high availability.

beginner

What is the role of the primary node in a replica set?

The primary node receives all write operations and replicates data to secondary nodes.

beginner

How does a secondary node in a replica set function?

A secondary node copies data from the primary and can serve read operations if configured, providing data redundancy.

intermediate

What is the purpose of the replica set configuration document?

It defines the members of the replica set, their roles, priorities, and settings for replication behavior.

intermediate

What happens if the primary node in a replica set fails?

The replica set automatically holds an election to select a new primary from the secondary nodes to maintain availability.

What is the main function of the primary node in a MongoDB replica set?

A Serve only read operations

B Handle all write operations

C Backup data to external storage

D Monitor network traffic

The primary node handles all write operations and replicates data to secondaries.

Which of the following is true about secondary nodes in a replica set?

A They can become primary through an election

B They reject all read operations

C They do not replicate data

D They control the replica set configuration

Secondary nodes replicate data and can become primary if elected.

What does the replica set configuration document NOT include?

A Member roles and priorities

B Replication settings

C List of replica set members

D User authentication credentials

User authentication credentials are managed separately, not in the replica set config.

How does a replica set maintain high availability?

A By automatic failover and elections

B By backing up data every hour

C By limiting connections to one client

D By disabling writes during failures

Replica sets use automatic failover and elections to keep the system available.

Which command initializes a replica set in MongoDB?

A mongo.startReplica()

B db.createReplica()

C rs.initiate()

D rs.start()

The rs.initiate() command starts the replica set configuration.

Explain the roles of primary and secondary nodes in a MongoDB replica set.

Think about who writes data and who copies it.

Describe how a MongoDB replica set ensures data availability when a node fails.

Focus on what happens when the primary goes down.