diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
index d60d94e9ae..1e9a9f295b 100644
--- a/docs/schemas/domaincommon.rng
+++ b/docs/schemas/domaincommon.rng
@@ -6460,7 +6460,7 @@
   </define>
   <define name="driveUnit">
     <data type="string">
-      <param name="pattern">[0-9]{1,2}</param>
+      <param name="pattern">[0-9]{1,5}</param>
     </data>
   </define>
   <define name="driveSCSIUnit">