Merge pull request #178387 from b-juche/patch-290

Repeat TTL consideration to AD article (SRE request ANF-16350)

Author: v-albemi

articles/azure-netapp-files/configure-ldap-extended-groups.md

@@ -13,7 +13,7 @@ ms.workload: storage
 ms.tgt_pltfrm: na
 ms.devlang: na
 ms.topic: how-to
-ms.date: 09/20/2021
+ms.date: 11/02/2021
 ms.author: b-juche
 ---
 # Configure ADDS LDAP with extended groups for NFS volume access
@@ -32,7 +32,7 @@ This article explains the considerations and steps for enabling LDAP with extend
 
 * You cannot modify the LDAP option setting (enabled or disabled) after you have created the volume.  
 
-* The following table describes the Time to Live (TTL) settings for the LDAP cache. You need to wait until the cache is refreshed before trying to access a file or directory through a client. Otherwise, an access denied message appears on the client. 
+* The following table describes the Time to Live (TTL) settings for the LDAP cache. You need to wait until the cache is refreshed before trying to access a file or directory through a client. Otherwise, an access or permission denied message appears on the client. 
 
     |     Error condition    |     Resolution    |
     |-|-|

articles/azure-netapp-files/create-active-directory-connections.md

@@ -13,7 +13,7 @@ ms.workload: storage
 ms.tgt_pltfrm: na
 ms.devlang: na
 ms.topic: how-to
-ms.date: 09/09/2021
+ms.date: 11/02/2021
 ms.author: b-juche
 ---
 # Create and manage Active Directory connections for Azure NetApp Files
@@ -88,6 +88,17 @@ Several features of Azure NetApp Files require that you have an Active Directory
 
 * For non-AD integrated DNS, you should add a DNS A/PTR record to enable Azure NetApp Files to function by using a “friendly name". 
 
+* The following table describes the Time to Live (TTL) settings for the LDAP cache. You need to wait until the cache is refreshed before trying to access a file or directory through a client. Otherwise, an access or permission denied message appears on the client. 
+
+    |     Error condition    |     Resolution    |
+    |-|-|
+    | Cache |  Default Timeout |
+    | Group membership list  | 24-hour TTL  |
+    | Unix groups  | 24-hour TTL, 1-minute negative TTL  |
+    | Unix users  | 24-hour TTL, 1-minute negative TTL  |
+
+    Caches have a specific timeout period called *Time to Live*. After the timeout period, entries age out so that stale entries do not linger. The *negative TTL* value is where a lookup that has failed resides to help avoid performance issues due to LDAP queries for objects that might not exist.”   
+
 ## Decide which Domain Services to use 
 
 Azure NetApp Files supports both [Active Directory Domain Services](/windows-server/identity/ad-ds/plan/understanding-active-directory-site-topology) (ADDS) and Azure Active Directory Domain Services (AADDS) for AD connections.  Before you create an AD connection, you need to decide whether to use ADDS or AADDS.