In this section, we will go through the implementation of a cluster in MongoDB using sharding and replica sets.
Note
A sharded cluster consists of three configuration processes, one or more replica sets, and one or more mongos routing processes.
You can view this at http://docs.mongodb.org/manual/reference/glossary/#term-sharded-cluster.
A sharded cluster in MongoDB consists of three components, configuration servers, shards (replica sets or mongod processes), and mongos. The mongos process is the query router for all clients.
Shards are replica sets that store each individual part of a database. In a development environment, you can use the mongod process instead of the replica set, but for production, it's recommended that you use the replica set because it provides better performance in high throughput. The replica set is made up of different mongod processes.