title: Numbers for diagnostics metrics of VM on portal.azure.com dashboard seem incorrect
body: <p>On <em>Azure</em>, I have a <strong>Linux VM</strong>. I enable <em>Diagnostics settings</em> on this VM 3 days ago.</p>
  
  <p><strong>The virtual machine has a 30 GB</strong> disk of which 16 are used. But Azure Monitor chart for <strong>"Filesystem free space" showing</strong> that I have <strong>149 GB</strong> free space and <strong>"Filesystem used space" 24.5 GB</strong>.</p>
  
  <p>Why is that? Is it correct? Can I debug this?</p>