diff --git a/_constraints b/_constraints
index 04fb88d..13a8856 100644
--- a/_constraints
+++ b/_constraints
@@ -2,7 +2,7 @@
 <constraints>
   <hardware>
     <disk>
-        <size unit="G">30</size>
+        <size unit="G">20</size>
     </disk>
     <memory>
       <size unit="M">4000</size>