Merge pull request #225864 from dennispadia/depadia-drsap

Include Windows strategy in SAP DR documentation

Author: denrea

articles/virtual-machines/workloads/sap/disaster-recovery-sap-guide.md

@@ -8,7 +8,7 @@ ms.author: depadia
 ms.service: virtual-machines-sap
 ms.topic: conceptual
 ms.workload: infrastructure-services
-ms.date: 11/22/2022
+ms.date: 01/31/2023
 ---
 
 # Disaster recovery guidelines for SAP application
@@ -42,7 +42,7 @@ To achieve DR for highly available SAP Web Dispatcher setup in primary region, y
 
 The SAP central services contain enqueue and message server, which is one of the SPOF of your SAP application. In an SAP system, there can be only one such instance, and it can be configured for high availability. Read [High Availability for SAP Central Service](sap-planning-supported-configurations.md#high-availability-for-sap-central-service) to understand the different high availability solution for SAP workload on Azure.
 
-Configuring high availability for SAP Central Services protects resources and processes from local incidents. To achieve DR for SAP Central Services, you can use Azure Site Recovery. Azure Site Recovery replicate VMs and the attached managed disks, but there are additional considerations for the DR strategy. Check the section below for more information, based on the operating system used for SAP central services.
+Configuring high availability for SAP Central Services protects resources and processes from local incidents. To achieve DR for SAP Central Services, you can use Azure Site Recovery. Azure Site Recovery replicates VMs and the attached managed disks, but there are additional considerations for the DR strategy. Check the section below for more information, based on the operating system used for SAP central services.
 
 #### [Linux](#tab/linux)
 
@@ -91,11 +91,44 @@ Irrespective of the operating system (SLES or RHEL) and its version, pacemaker r
 >[!Note]
 > We recommend to have same fencing mechanism for both primary and DR region for ease of operation and failover. It is not advised to have different fencing mechanism after failover to DR site.
 
+#### [Windows](#tab/windows)
+
+For SAP system, the redundancy of SPOF component in the primary region is achieved by configuring high availability. To achieve similar high availability setup in the disaster recovery region after failover, you need to consider additional points like cluster reconfiguration, SAP shared directories availability, alongside of replicating VMs and attached managed disk to DR site using Azure Site Recovery. On Windows, the high availability of SAP application can be achieved using Windows Server Failover Cluster (WSFC). The diagram below shows the different components involved in configuring high availability of SAP central services with WSFC. Each component must be evaluated to achieve similar high availability set up in the DR site. If you have configured SAP Web Dispatcher using WSFC, similar consideration would apply as well.
+
+![SAP system Windows architecture](media/disaster-recovery/disaster-recovery-sap-windows-architecture.png)
+
+##### SAP system configured with File share
+
+If you've configured your SAP system using file share on primary region, you need to make sure all components and the data in the file share (SMB on Azure Files, SMB on ANF) are replicated to the disaster recovery region if there is failover. You can use Azure Site Recovery to replicate the cluster VMs and other application server VMs to the disaster recovery region. There are some additional considerations that are outlined below.
+
+###### Load balancer
+
+Azure Site Recovery replicates VMs to the DR site, but it doesn’t replicate Azure load balancer. You'll need to create a separate internal load balancer on DR site beforehand or after failover. If you create internal load balancer beforehand, create an empty backend pool and add VMs after the failover event.
+
+###### Quorum (cloud witness)
+
+If you have configured cluster with cloud witness at its quorum mechanism, then you would need to create a separate storage account on DR region. On the event of failover, quorum setting must be updated with the new storage account name and access keys.
+
+###### Windows server failover cluster
+
+If there is failover, SAP ASCS/ERS VMs configured with WSFC won’t work out-of-the-box. Additional reconfiguration is required to start SAP system on the DR region.
+
+Read [SAP NetWeaver HA deployment with File Share running on Windows failover to DR Region using ASR](https://techcommunity.microsoft.com/t5/running-sap-applications-on-the/sap-netweaver-ha-deployment-with-file-share-running-on-windows/ba-p/3727034) blog to learn more about the additional steps that are required in the DR region.
+
+###### File share directories
+
+The high availability setup of SAP NetWeaver or ABAP platform uses enqueue replication server for achieving application level redundancy for the enqueue service of SAP system with WSFC configuration. The high availability setup of SAP central services (ASCS and ERS) with file share uses SMB shares. You will need to make sure that the SAP binaries and data on these SMB shares are replicated to the DR site. Azure Site Recovery replicates VMs and local managed disk attached, but it doesn't replicate the file shares. Choose the replication method, based on the type of file share storage you've configured for the setup. The cross regional replication methodology for each storage is presented at abstract level. You need to confirm exact steps to replicate storage and perform testing. 
+
+| SAP file share directories | Cross region replication mechanism                           |
+| -------------------------- | ------------------------------------------------------------ |
+| SMB on Azure Files         | [Robocopy](../../../storage/files/storage-files-migration-robocopy.md) |
+| SMB on Azure NetApp Files  | [Cross Region Replication](../../../azure-netapp-files/cross-region-replication-introduction.md) |
+
 ---
 
 ### SAP Application Servers
 
-In primary region, the redundancy of SAP application servers is achieved by installing instances in multiple VMs. To have DR for SAP application servers, [Azure Site Recovery](../../../site-recovery/azure-to-azure-tutorial-enable-replication.md) can be set up for each application server VM. For shared storages (transport filesystem, interface data filesystem) that are attached to the application servers, follow the appropriate DR practice based on the type of [shared storage](disaster-recovery-overview-guide.md#storage).
+In the primary region, the redundancy of the SAP application servers is achieved by installing instances in multiple VMs. To have DR for SAP application servers, [Azure Site Recovery](../../../site-recovery/azure-to-azure-tutorial-enable-replication.md) can be set up for each application server VM. For shared storages (transport filesystem, interface data filesystem) that is attached to the application servers, follow the appropriate DR practice based on the type of [shared storage](disaster-recovery-overview-guide.md#storage).
 
 ### SAP Database Servers