diff -Naur drbd-utils-8.9.2.orig/documentation/v84/drbdsetup.xml drbd-utils-8.9.2/documentation/v84/drbdsetup.xml
--- drbd-utils-8.9.2.orig/documentation/v84/drbdsetup.xml	2015-07-20 16:06:52.950294231 +0800
+++ drbd-utils-8.9.2/documentation/v84/drbdsetup.xml	2015-07-20 17:56:21.106826315 +0800
@@ -1694,6 +1694,15 @@
               <para>Clears the sync bitmap in addition to generating a new current UUID.</para>
             </listitem>
           </varlistentry>
+
+          <varlistentry>
+            <term><option>--zap-devices</option></term>
+
+            <listitem>
+              <para>Start to zeroing out the device on both side in addition to generating 
+              a new current UUID .</para>
+            </listitem>
+          </varlistentry>
         </variablelist></para>
 
       <para>This can be used to skip the initial sync, if you want to start from scratch. This