title: need explain about atop logging system
body: <p>I'm not a infra/system engineer, but I need to monitor device resource history.</p>
  <p>I heard 'atop' is a good tool to monitor resource device, so I install in it.</p>
  <p>Document says that atop automatically generate log in '/var/log/atop/atop_XXXXXX/'.</p>
  <p>I found that logs there, but some day was not recorded...</p>
  <p>Is there anyone to explain about how does atop logging system execute? and how to manipulate it?</p>
  <p>Thanks in advance.</p>