title: PHP session times out after only a few minutes
body: <p>We have a PHP app (SilverStripe) on a cPanel LAMP shared hosting server. The CMS user is losing their session every couple of minutes. Here are some session settings based on <code>phpinfo()</code> on the hosting platform:</p>
  
  <pre><code>session.gc_maxlifetime = 0
  session.gc_divisor = 100
  session.gc_probability = 1
  session.save_handler = files
  session.save_path = /tmp
  session.cookie_lifetime = 0
  </code></pre>
  
  <p>There is no session management in the PHP code. In fact SilverStripe CMS actually pings the server every 5 minutes to keep the session alive but timeouts are happening way before then.</p>
  
  <p>What could cause this?</p>