diff --git a/admin_manual/configuration_server/config_sample_php_parameters.rst b/admin_manual/configuration_server/config_sample_php_parameters.rst
index 2934d93d7..6bbc80db2 100644
--- a/admin_manual/configuration_server/config_sample_php_parameters.rst
+++ b/admin_manual/configuration_server/config_sample_php_parameters.rst
@@ -1671,6 +1671,18 @@ calculation, defaults to false.
 
 Defaults to ``false``
 
+::
+
+	'external_storage.auth_availability_delay' => 1800,
+
+When an external storage is unavailable for some reasons, it will be flagged
+as such for 10 minutes. When the trigger is a failed authentication attempt
+the delay is higher and can be controlled with this option. The motivation
+is to make account lock outs at Active Directories (and compatible) more
+unlikely.
+
+Defaults to ``1800`` (seconds)
+
 ::
 
 	'filesystem_check_changes' => 0,