title: Disk is full, but can't find which folder take space
body: <p>I'm trying to find out which folder in my VPS take the most of disk usge, the result of df -h command show that my disk storage has 40GB and I used 38 Gb. </p>
  
  <p>But when I calculate the size of root folder using ncdu (using command: ncdu /), it show that I only used 8.9 Gb:
  Can anyone help me to figure out which files/folders take nearly 30 Gb of my disk</p>