Merge pull request #219405 from msftrobiro/patch-3

Update SAP deployment checklist

Author: prmerger-automator[bot]

articles/virtual-machines/workloads/sap/sap-deployment-checklist.md

@@ -131,7 +131,7 @@ We recommend that you set up and validate a full HADR solution and security desi
   - Use [Azure premium storage](/azure/virtual-machines/disks-types#premium-ssds), [premium storage v2](/azure/virtual-machines/disks-types#premium-ssd-v2) for all production grade SAP environments and when ensuring high SLA. For some DBMS, Azure NetApp Files can be used for [large parts of the overall storage requirements](./planning-guide-storage.md#azure-netapp-files-anf).
   -	At a minimum, use [Azure standard SSD](/azure/virtual-machines/disks-types#standard-ssds) storage for VMs that represent SAP application layers and for deployment of DBMSs that aren't performance sensitive. Keep in mind different Azure storage types influence the [single VM availability SLA](https://azure.microsoft.com/support/legal/sla/virtual-machines).
   - In general, we don't recommend the use of [Azure standard HDD](./planning-guide-storage.md#azure-standard-hdd-storage) disks for SAP.
-  - For the different DBMS types, check the [generic SAP-related DBMS documentation](./dbms_guide_general.md) and DBMS-specific documentation that the first document points to. Use disk striping over multiple disks with premium storage (v1 or v2) for database data and log area.
+  - For the different DBMS types, check the [generic SAP-related DBMS documentation](./dbms_guide_general.md) and DBMS-specific documentation that the first document points to. Use disk striping over multiple disks with premium storage (v1 or v2) for database data and log area. Verify lvm disk striping is active and with correct stripe size with command 'lvs -a -o+lv_layout,lv_role,stripes,stripe_size,devices' on Linux, see storage spaces properties on Windows. 
   - For optimal storage configuration with SAP HANA, see [SAP HANA Azure virtual machine storage configurations](./hana-vm-operations-storage.md).
   - Use LVM for all disks on Linux VMs, as it allows easier management and online expansion. This includes volumes on single disks, for example /usr/sap.
 
@@ -153,9 +153,8 @@ We recommend that you set up and validate a full HADR solution and security desi
 
 - **High availability and disaster recovery deployments**
   - Always use standard load balancer for clustered environments. Basic load balancer will be [retired](/azure/load-balancer/skus).
-  - If you deploy the SAP application layer without defining a specific availability zone, make sure that all VMs that run SAP dialog instances or middleware instances of a single SAP system are deployed in an [availability set](/azure/virtual-machines/availability-set-overview).
-  - If you don't need high availability for SAP Central Services and the DBMS, you can deploy these VMs into the same availability set as the SAP application layer.
-  - When you protect SAP Central Services and the DBMS layer for high availability by using passive replication, place the two nodes for SAP Central Services in one separate availability set and the two DBMS nodes in another availability set.
+  - If you deploy the SAP application layer without defining a specific availability zone, make sure that all VMs that run SAP application instances of a single SAP system are deployed in an [availability set](/azure/virtual-machines/availability-set-overview).
+  - When you protect SAP Central Services and the DBMS layer for high availability by using passive replication, place the two nodes for SAP Central Services in one separate availability set and the two DBMS nodes in another availability set. Do not mix application VM roles inside an availability set.
   - If you deploy into [availability zones](./sap-ha-availability-zones.md), you can't combine with availability sets. But you do need to make sure you deploy the active and passive central services nodes into two different availability zones. Use two availability zones that have the lowest latency between them.
   - If you're using Azure Load Balancer together with Linux guest operating systems, check that the Linux network parameter net.ipv4.tcp_timestamps is set to 0. This recommendation conflicts with recommendations in older versions of [SAP note 2382421](https://launchpad.support.sap.com/#/notes/2382421). The SAP note is now updated to state that this parameter needs to be set to 0 to work with Azure load balancers.
 
@@ -333,4 +332,4 @@ See these articles:
 > [!div class="checklist"]
 > * [Azure planning and implementation for SAP NetWeaver](./planning-guide.md)
 > *	[Considerations for Azure Virtual Machines DBMS deployment for SAP workloads](./dbms_guide_general.md)
-> *	[Azure Virtual Machines deployment for SAP NetWeaver](./deployment-guide.md)
+> *	[Azure Virtual Machines deployment for SAP NetWeaver](./deployment-guide.md)