diff --git a/src/middlewared/middlewared/plugins/pool.py b/src/middlewared/middlewared/plugins/pool.py
index 63ea4c292ea8..1c7d9e6a9634 100644
--- a/src/middlewared/middlewared/plugins/pool.py
+++ b/src/middlewared/middlewared/plugins/pool.py
@@ -56,7 +56,7 @@ def to_json_schema(self, parent=None):
 
 
 def _none(x):
-    if x is None:
+    if x in (0, None):
         return 'none'
     return x