title: Do we need replicaSet in connection URI of MongoDB
body: <p>When connecting to mongo cluster do we need replicaSet option in connection URI like below</p>
  <pre><code>mongodb://db1.example.net:27017,db2.example.net:2500/?replicaSet=test
  </code></pre>
  <p>What happens if replicaSet option is not used but all the nodes are given in connection URI like below</p>
  <pre><code>mongodb://db1.example.net:27017,db2.example.net:2500/
  </code></pre>
  <p>What is the advantage of giving and not giving replicaSet in the connection URI for the above 2 cases.</p>