title: All the possible reasons that the Linux CPU(s) are Off-line?
body: <p>Stack Overflow, 
  We have a server running Red-hat 6 for a period in which we have 2 sockets * 8 cores * 2 threads, since former workmates have left and there is no document regarding this fields: we are now investigating a 'Off-line CPU(s) list' on two specific questions: 
   - Q1. What have caused those CPU(s) offline?
   - Q2. When are those CPU(s) offline caused?</p>
  
  <p>Could there be an enumeration about all the techniques that should cause the CPU(s) to be showing this status?</p>
  
  <p>The "Off-line CPU(s) is showing like below: </p>
  
  <p><a href="https://i.stack.imgur.com/VueQW.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/VueQW.jpg" alt="enter image description here"></a></p>