MongoDB Replica Sets: Basic Configuration for Data Security

MongoDB replica sets are a core mechanism for ensuring data security, addressing single-point failure issues through multi-node collaboration to guarantee data integrity and continuous service availability. They consist of three roles: the Primary (handles write operations and synchronizes data), the Secondary (replicates data and can become Primary), and the Arbiter (only votes for Primary without storing data). For basic configuration, start three nodes (with different ports) for Primary, Secondary, and Arbiter. Initialize with `rs.initiate()`, add nodes using `rs.add()`, and add the Arbiter with `rs.addArb()`. Verify status via `rs.status()`. Data security relies on: data redundancy (primary-secondary synchronization), automatic failover (election mechanism), and read-write separation (secondary nodes share read requests). Key considerations: Data directories must be independent. Production environments require at least 3 nodes (including the Arbiter) to ensure valid voting. Monitor status during maintenance using `rs.status()` and `db.printSlaveReplicationInfo()`. After Primary failure, the replica set automatically elects a new Primary without manual intervention.