title: How do I manage MongoDB connections in a Node.js web application?
body: <p>I'm using the <a href="https://github.com/mongodb/node-mongodb-native" rel="noreferrer">node-mongodb-native</a> driver with MongoDB to write a website.</p>
  
  <p>I have some questions about how to manage connections:</p>
  
  <ol>
  <li><p>Is it enough using only one MongoDB connection for all requests? Are there any performance issues? If not, can I setup a global connection to use in the whole application?</p></li>
  <li><p>If not, is it good if I open a new connection when request arrives, and close it when handled the request? Is it expensive to open and close a connection?</p></li>
  <li><p>Should I use a global connection pool? I hear the driver has a native connection pool. Is it a good choice?</p></li>
  <li><p>If I use a connection pool, how many connections should be used?</p></li>
  <li><p>Are there other things I should notice?</p></li>
  </ol>