title: -XX:MaxPermSize with or without -XX:PermSize
body: <p>We've run into a <strong>Java.lang.OutOfMemoryError: PermGen space</strong> error and looking at the tomcat JVM params, other than the <code>-Xms</code> and <code>-Xmx</code> params we also specify <code>-XX:MaxPermSize=128m</code>. After a bit of profiling I can see occasionally garbage collection happening on the PermGen space saving it from running full.</p>
  
  <p>My question is: other than increasing the <code>-XX:MaxPermSize</code> what would be the difference if I specify as well <code>-XX:PermSize</code>? I know the total memory then would be <strong>Xmx+maxPermSize</strong> but is there any other reason why <code>-XX:PermSize</code> should <strong>not</strong> be there when <code>-XX:MaxPermSize</code> is specified?</p>
  
  <p>Please do share if you have real-world experience dealing with these JVM parameters.</p>
  
  <p>ps. The JVM is HotSpot 64bit Server VM build 16.2-b04</p>