Q37: What is a Replica Set in MongoDB? Explain Primary, Secondary, and Arbiter nodes.
A Replica Set is a group of mongod instances that maintain the same data set for high availability and redundancy:
- Primary Node: Receives all write operations.
- Secondary Nodes: Replicate the Primary's oplog and apply operations asynchronously. Can serve read queries.
- Arbiter Node: Holds no data; participates strictly in elections to break tie votes.
Key Takeaways
- Ensures automatic failover and redundancy.
- Contains 1 Primary and 1+ Secondary nodes.
Knowledge Check
What is the primary role of an Arbiter node in a MongoDB Replica Set?