title: I am not able to set Alert for grafana graph
body: <p>I have set alerts for Disk usage and now I want set alerts for Memory usage but I am not able to set it is giving error <code>FAILED TO TEST RULE</code>. Axes B is used and Axes C is Total.</p>
  
  <p><a href="https://i.stack.imgur.com/6Xfju.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/6Xfju.png" alt="enter image description here"></a></p>
  
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