diff -r 0cf10429ad39 -r 28bf94d062a9 server/sources/native.py
--- a/server/sources/native.py	Mon Feb 07 18:19:36 2011 +0100
+++ b/server/sources/native.py	Mon Feb 07 18:19:39 2011 +0100
@@ -45,8 +45,10 @@
 from logilab.database import get_db_helper
 
 from yams import schema2sql as y2sql
+from yams.schema import role_name
 
-from cubicweb import UnknownEid, AuthenticationError, ValidationError, Binary, UniqueTogetherError
+from cubicweb import (UnknownEid, AuthenticationError, ValidationError, Binary,
+                      UniqueTogetherError)
 from cubicweb import transaction as tx, server, neg_role
 from cubicweb.schema import VIRTUAL_RTYPES
 from cubicweb.cwconfig import CubicWebNoAppConfiguration
@@ -310,6 +312,13 @@
         #      consuming, find another way
         return SQLAdapterMixIn.get_connection(self)
 
+    def check_config(self, source_entity):
+        """check configuration of source entity"""
+        if source_entity.host_config:
+            msg = source_entity._cw._('the system source has its configuration '
+                                      'stored on the file-system')
+            raise ValidationError(source_entity.eid, {role_name('config', 'subject'): msg})
+
     def add_authentifier(self, authentifier):
         self.authentifiers.append(authentifier)
         authentifier.source = self