title: Cacti graphs are not showing any data
body: <p>I am cacti graphs to measure the performance of metrics in ubuntu.</p>
  
  <p>I am not able to see any graphs not blank graphs .</p>
  
  <p>So as a debugging measure , I went to the logger file to see the if the script what I am using is returning values or not.</p>
  
  <p>And yes it returns values .</p>
  
  <p>But the rrd files are not getting updated .</p>
  
  <p>One more thing I noticed is that , the log files are under www-data .</p>
  
  <p>What is happening  and why not the graphs are generating ?</p>