title: 64-bit JVM limited to 300GB of memory?
body: <p>I am attempting to run a Java application on a cluster computing environment (IBM LSF running CentOS release 6.2 Final) that can provide me with up to 1TB of RAM space.</p>
  <p>I could create a JVM with up to 300GB of maximum memory (Xmx), although I need more than that (I can provide details, if requested).</p>
  <p>However, it seems to be impossible to create a JVM with more than 300GB of maximum memory using the Xmx option. To be more specific, I get the classic error message:</p>
  <blockquote>
  <p>Error occurred during initialization of VM.</p>
  <p>Could not reserve enough space for object heap.</p>
  </blockquote>
  <p>The details of my (64-bit) JVM are below:</p>
  <blockquote>
  <p>OpenJDK Runtime Environment (IcedTea6 1.10.6) (rhel-1.43.1.10.6.el6_2-x86_64)</p>
  <p>OpenJDK 64-Bit Server VM (build 20.0-b11, mixed mode)</p>
  </blockquote>
  <p>I've also tried with a Java 7 64-bit JVM but I've had exactly the same problem.</p>
  <p>Moreover, I tried to create a JVM to run a HelloWorld.jar, but still JVM creation fails if you ask for more than -Xmx300G, so I don't think it has anything to do with the specific application.</p>
  <hr />
  <p>Does anyone have any idea why I cannot create a JVM with more than 300G of max memory?</p>
  <p>Can anyone please suggest a solution/workaround?</p>