<volume type='file'>
  <name>test.iso</name>
  <source>
  </source>
  <capacity unit='bytes'>1048576</capacity>
  <allocation unit='bytes'>1048576</allocation>
  <target>
    <path>/var/lib/libvirt/images/test.iso</path>
    <format type='iso'/>
  </target>
</volume>
