diff --git a/perl-xCAT/xCAT/Utils.pm b/perl-xCAT/xCAT/Utils.pm
index 39342a3ec..f0258573c 100644
--- a/perl-xCAT/xCAT/Utils.pm
+++ b/perl-xCAT/xCAT/Utils.pm
@@ -3598,7 +3598,9 @@ sub get_site_Master
 
 	 example: $sn =xCAT::Utils->get_ServiceNode(\@nodes,$service,"MN");
 	  $sn =xCAT::Utils->get_ServiceNode(\@nodes,$service,"Node");
-
+        Note: this rountine is important to hierarchical support in xCAT
+              and used in many places.  Any changes to the logic should be
+              reviewed by xCAT architecture
 =cut
 
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