What is the difference between a replica set and a sharded cluster in MongoDB?

• Replica Set: A group of MongoDB servers that maintain the same data. It provides

high availability and data redundancy by replicating data across multiple servers. If

the primary server goes down, one of the secondaries can be promoted to primary

automatically.

• Sharded Cluster: Used for horizontal scaling. It splits data across multiple servers

(shards) based on a shard key. Each shard holds a portion of the data, and a

mongos router directs queries to the correct shard. Sharding helps manage large

datasets by distributing the load.