Clarification around system indices

Author: aetter

docs/alerting/settings.md

@@ -10,7 +10,7 @@ nav_order: 5
 
 ## Alerting indices
 
-The alerting feature creates several indices and one alias. Don't delete these or modify their contents without using the alerting APIs.
+The alerting feature creates several indices and one alias. The security plugin demo script configures them as [system indices](../../security/configuration/system-indices/) for an extra layer of protection. Don't delete these indices or modify their contents without using the alerting APIs.
 
 Index | Purpose
 :--- | :---

docs/security/configuration/system-indices.md

@@ -8,11 +8,9 @@ nav_order: 15
 
 # System indices
 
-By default, Open Distro for Elasticsearch has several protected system indices. Even if your user account has read permissions for all indices, you can't directly access the data in these system indices.
+By default, Open Distro for Elasticsearch has a protected system index, `.opendistro_security`, which you create using [securityadmin.sh](../security-admin/). Even if your user account has read permissions for all indices, you can't directly access the data in this system index.
 
-The first and most critical index is `.opendistro_security`, which stores the security configuration for your cluster. The demo configuration creates this index automatically, but when you configure the plugin manually, you create it when you first run [securityadmin.sh](../security-admin/).
-
-You can see other system indices in `elasticsearch.yml`:
+You can add additional system indices in in `elasticsearch.yml`. In addition to automatically creating `.opendistro_security`, the demo configuration adds several indices for the various Open Distro for Elasticsearch plugins that integrate with the security plugin:
 
 ```yml
 opendistro_security.system_indices.enabled: true