<volume type='file'>
  <name>sparse.img</name>
  <key>/var/lib/libvirt/images/sparse.img</key>
  <source>
  </source>
  <capacity unit='bytes'>10000000000</capacity>
  <allocation unit='bytes'>0</allocation>
  <target>
    <path>/var/lib/libvirt/images/sparse.img</path>
    <format type='raw'/>
    <permissions>
      <mode>00</mode>
      <owner>744</owner>
      <group>0</group>
    </permissions>
  </target>
  <backingStore>
    <path>/var/lib/virt/images/master.img</path>
    <format type='vmdk'/>
    <permissions>
      <mode>0744</mode>
      <owner>1</owner>
      <group>1</group>
      <label>virt_image_t</label>
    </permissions>
  </backingStore>
</volume>