title: Not able to get correct number of Open File descriptor from node-exporter metrics
body: <p>We are using node_exporter version 0.18.0</p>
  
  <p>In Grafana Node Exporter dashboards, it shows the no of open file descriptors used by the Node Exporter process only, not the FDS used by the OS in that instance.</p>
  
  <p>We are running node-exporter from root user.</p>
  
  <p><strong>System Stats:</strong></p>
  
  <p>Output of <code>lsof | wc -l</code> is <code>446732</code></p>
  
  <p>open files                      (-n) 400000</p>
  
  <p><strong>Node Exporter Metrics:</strong></p>
  
  <p>node_filefd_allocated 3232</p>
  
  <p>node_filefd_maximum 1.508219e+06</p>
  
  <p>node_scrape_collector_duration_seconds{collector="filefd"} 4.4016e-05</p>
  
  <p>process_max_fds 1024</p>
  
  <p>process_open_fds 9</p>