diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
index 5b7aa10..48eafa4 100644
--- a/docs/formatdomain.html.in
+++ b/docs/formatdomain.html.in
@@ -349,6 +349,7 @@
             <encryption type='...'>
               ...
             </encryption>
+            <shareable/>
           </disk>
           ...</pre>
 
@@ -389,6 +390,11 @@
         the <a href="formatstorageencryption.html">Storage Encryption</a> page
         for more information.
       </dd>
+      <dt><code>shareable</code></dt>
+      <dd>If present, this indicates the device is expected to be shared
+          between domains (assuming the hypervisor and OS support this),
+          which means that caching should be desactivated for that device.
+      </dd>
     </dl>
 
     <h4><a name="elementsUSB">USB and PCI devices</a></h4>