diff --git a/docs/config.rst b/docs/config.rst
index 91debf17..df746f5b 100644
--- a/docs/config.rst
+++ b/docs/config.rst
@@ -200,6 +200,8 @@ Default
 Also used by
   :ref:`webui`, to link to log files
 
+.. attention:: Each ``*_dir`` setting must point to a different directory.
+
 .. _items_dir:
 
 items_dir
@@ -221,6 +223,8 @@ Default
 Also used by
   :ref:`webui`, to link to item feeds
 
+.. attention:: Each ``*_dir`` setting must point to a different directory.
+
 .. _jobs_to_keep:
 
 jobs_to_keep
@@ -325,6 +329,8 @@ The directory in which to write project eggs.
 Default
   ``eggs``
 
+.. attention:: Each ``*_dir`` setting must point to a different directory.
+
 Job storage options
 -------------------
 
@@ -376,6 +382,8 @@ Used by
   -  :ref:`spiderqueue` (``scrapyd.spiderqueue.SqliteSpiderQueue``)
   -  :ref:`jobstorage` (``scrapyd.jobstorage.SqliteJobStorage``)
 
+.. attention:: Each ``*_dir`` setting must point to a different directory.
+
 .. _config-services:
 
 Services