title: docker with no volume running, where does container system file store?
body: <p>If I run a container with no volume specified, where does container system file store ?</p>
  <ul>
  <li><code>docker run -it c_name i_name:tag</code></li>
  </ul>
  <p>when I run a container without volume, only container folder created in <code>/var/lib/docker/container</code>, but I If I create a large file in container file system, where does it stored on host? Because I want to know if it will cause occupying disk size issue.</p>