title: Hadoop namenode metadata
body: <p>I am a bit confused by the Hadoop architecture. </p>
  
  <ol>
  <li><p>What kind of file metadata is stored in Hadoop Namenode? From Hadoop wiki, it says Namenode stores the entire system namespace. Does information like last modified time, created time, file size, owner, permissions and etc stored in Namenode? </p></li>
  <li><p>Does datanode store any metadata information?</p></li>
  <li><p>There is only one Namenode, can the metadata data exceed the server's limit? </p></li>
  <li><p>If a user wants to download a file from Hadoop, does he have to download it from the Namenode? I found the below architecure picture from web, it shows a client can direct write data to datanode? Is it true? 
  <img src="https://i.stack.imgur.com/7yiEs.gif" alt="enter image description here"></p></li>
  </ol>
  
  <p>Thanks!!!!!!!</p>