updated the suse and rhel docs for sap ascs/ers cluster with note for 3 node cluster

Author: Anjan Banerjee

articles/sap/workloads/high-availability-guide-rhel.md

@@ -524,7 +524,21 @@ The following items are prefixed with:
     #      rsc_sap_NW1_ERS02  (ocf::heartbeat:SAPInstance):   Started nw1-cl-0
     ```
 
-10. **[A]** Add firewall rules for ASCS and ERS on both nodes.
+10. **[1]** Run the following step to configure `priority-fencing-delay` (applicable only as of pacemaker-2.0.4-6.el8 or higher).
+
+    > [!NOTE]
+    > If you have a two-node cluster, you have the option to configure the `priority-fencing-delay` cluster property. This property introduces additional delay in fencing a node that has higher total resource priority when a split-brain scenario occurs. For more information, see [Can Pacemaker fence the cluster node with the fewest running resources?](https://access.redhat.com/solutions/5110521)
+    >
+    > The property `priority-fencing-delay` is applicable for pacemaker-2.0.4-6.el8 version or higher. If you set up `priority-fencing-delay` on an existing cluster, make sure to clear the `pcmk_delay_max` setting in the fencing device.  
+
+    ```bash
+    sudo pcs resource defaults update priority=1
+    sudo pcs resource update rsc_sap_NW1_ASCS00 meta priority=10
+
+    sudo pcs property set priority-fencing-delay=15s
+    ```
+
+11. **[A]** Add firewall rules for ASCS and ERS on both nodes.
 
     ```bash
     # Probe Port of ASCS
@@ -535,6 +549,12 @@ The following items are prefixed with:
     sudo firewall-cmd --zone=public --add-port={62102,3202,3302,50213,50214,50216}/tcp
     ```
 
+> [!Note]
+> SAP ASCS/ERS cluster can be extended from 2-node to 3-node cluster with 3rd node as a spare node for failover of ASCS or ERS services.
+> - 3-node setup can only be used for SAP systems using SAP Enqueue Replication Server 2 (ENSA2).
+> - The cluster property ‘priority-fencing-delay’ should not be used in a 3-node cluster.
+
+
 ## SAP NetWeaver application server preparation
 
 Some databases require that the database instance installation runs on an application server. Prepare the application server VMs to be able to use them in these cases.
@@ -725,7 +745,7 @@ Follow these steps to install an SAP application server.
         rsc_sap_NW1_ERS02  (ocf::heartbeat:SAPInstance):   Started nw1-cl-0
    ```
 
-1. Simulate a node crash.
+2. Simulate a node crash.
 
    Resource state before starting the test:
 
@@ -798,7 +818,7 @@ Follow these steps to install an SAP application server.
         rsc_sap_NW1_ERS02  (ocf::heartbeat:SAPInstance):   Started nw1-cl-1
    ```
 
-1. Block network communication.
+3. Block network communication.
 
    Resource state before starting the test:
 
@@ -827,14 +847,17 @@ Follow these steps to install an SAP application server.
 
    By enabling the `priority-fencing-delay` property, the cluster introduces a delay in the fencing action, specifically on the node hosting ASCS resource, allowing the node to win the fence race.
 
+   > [!NOTE]
+   > The property priority-fencing-delay is only applicable for ENSA2 running on two-node cluster.
+
    Run the following command to delete the firewall rule.
 
    ```bash
     # If the iptables rule set on the server gets reset after a reboot, the rules will be cleared out. In case they have not been reset, please proceed to remove the iptables rule using the following command.
     iptables -D INPUT -s 10.0.0.8 -j DROP; iptables -D OUTPUT -d 10.0.0.8 -j DROP
    ```
 
-1. Kill the message server process.
+4. Kill the message server process.
 
    Resource state before starting the test:
 
@@ -881,7 +904,7 @@ Follow these steps to install an SAP application server.
         rsc_sap_NW1_ERS02  (ocf::heartbeat:SAPInstance):   Started nw1-cl-0
    ```
 
-1. Kill the enqueue server process.
+5. Kill the enqueue server process.
 
    Resource state before starting the test:
 
@@ -932,7 +955,7 @@ Follow these steps to install an SAP application server.
         rsc_sap_NW1_ERS02  (ocf::heartbeat:SAPInstance):   Started nw1-cl-1
    ```
 
-1. Kill the enqueue replication server process.
+6. Kill the enqueue replication server process.
 
    Resource state before starting the test:
 
@@ -982,7 +1005,7 @@ Follow these steps to install an SAP application server.
         rsc_sap_NW1_ERS02  (ocf::heartbeat:SAPInstance):   Started nw1-cl-1
    ```
 
-1. Kill the enqueue `sapstartsrv` process.
+7. Kill the enqueue `sapstartsrv` process.
 
    Resource state before starting the test:
 

articles/sap/workloads/high-availability-guide-suse-nfs-azure-files.md

@@ -591,7 +591,7 @@ The following items are prefixed with either **[A]** - applicable to all nodes,
     #### [ENSA2](#tab/ensa2)
 
     > [!NOTE]
-    > If virtual machines without public IPs are added to the backend pool of an internal Standard Azure load balancer, they won�t have internet access unless you set up extra routing to public endpoints. For more information, see [SUSE Linux Enteprise Server high availability extension administration guide](https://documentation.suse.com/sle-ha/15-SP3/single-html/SLE-HA-administration/#pro-ha-storage-protect-fencing).
+    > If you have a two-node cluster running ENSA2, you have the option to configure priority-fencing-delay cluster property. This property introduces additional delay in fencing a node that has higher total resource priority when a split-brain scenario occurs. For more information, see [SUSE Linux Enteprise Server high availability extension administration guide](https://documentation.suse.com/sle-ha/15-SP3/single-html/SLE-HA-administration/#pro-ha-storage-protect-fencing).
     >
     > The property priority-fencing-delay is only applicable for ENSA2 running on two-node cluster.
 

articles/sap/workloads/high-availability-guide-suse.md

@@ -607,6 +607,12 @@ sudo crm_mon -r
 #      rsc_sap_NW1_ERS02  (ocf::heartbeat:SAPInstance):   Started nw1-cl-0
 ```
 
+> [!Note]
+> SAP ASCS/ERS cluster can be extended from 2-node to 3-node cluster with 3rd node as a spare node for failover of ASCS or ERS services.
+> - 3-node setup can only be used for SAP systems using SAP Enqueue Replication Server 2 (ENSA2).
+> - The cluster property ‘priority-fencing-delay’ should not be used in a 3-node cluster.
+
+
 ## SAP NetWeaver application server preparation
 
 Some databases require that the database instance installation is executed on an application server. Prepare the application server virtual machines to be able to use them in these cases.
@@ -1032,6 +1038,9 @@ The following tests are a copy of the test cases in the best practices guides of
 
    Additionally, in ENSA 2 configuration, to prioritize the node hosting the ASCS resource over the other node during a split brain scenario, it's recommended to configure [`priority-fencing-delay`](https://documentation.suse.com/sle-ha/15-SP3/single-html/SLE-HA-administration/#pro-ha-storage-protect-fencing) property in the cluster. Enabling priority-fencing-delay property allows the cluster to introduce an additional delay in the fencing action specifically on the node hosting the ASCS resource, allowing the ASCS node to win the fence race.
 
+   > [!NOTE]
+   > The property priority-fencing-delay is only applicable for ENSA2 running on two-node cluster.
+
    Execute below command to delete the firewall rule.
 
    ```bash