Architecture of replica sets

After learning the replication process, we can go ahead and learn about the replica set architecture. In order to create a readily available MongoDB server, you can simply use the replica set network.

So, what is replica set?

A replica set is a group of mongod instances that host the same dataset (http://docs.mongodb.org/manual/core/replication-introduction/).

Each replica set consists of different members and each one is responsible for a particular task. The following list shows you all the possible roles for each member:

• Primary: A primary node is responsible for accepting all read/write operations from clients. Each replica set can have one and only one primary node. Under some conditions, a primary node can become secondary or a secondary node can become primary by an election process.

• Secondary: The secondary nodes host the same dataset as primary nodes. Each replica set can have one or more secondary nodes. It's possible that a secondary node changes its...