Chapter 1. Overview
This document describes how to use the RHEL HA Add-On on RHEL 8 to set up an HA cluster to automate a ‘performance-optimized’ SAP HANA Scale-Up System Replication setup.
‘Performance-optimized’ means that there is only a single SAP HANA instance running on each node that has control over most of the resources (CPU, RAM) on each node, which means the SAP HANA instances can run with as much performance as possible. Since the secondary SAP HANA instance is configured to pre-load all data in this scenario, a takeover in case of a failure of the primary SAP HANA instance should happen quickly.
The following diagram shows an overview of what the setup looks like:
With a ‘performance-optimized’ SAP HANA System Replication setup it is also possible to use the Active/Active (Read Enabled) SAP HANA System Replication configuration, which will allow read-only access for clients on the secondary SAP HANA instance. In addition to the basic setup for managing ‘performance-optimized ‘ SAP HANA Scale-Up System Replication this document also provides optional instructions for the additional cluster configuration that is required for managing an Active/Active (Read Enabled) SAP HANA Scale-Up System Replication configuration.
The resource agents and the cluster configuration used for the setup described in this document have been developed based on guidelines provided by SAP in SAP Note 2063657 - SAP HANA System Replication Takeover Decision Guideline.
This document does not cover the installation and configuration of RHEL 8 for running SAP HANA or the SAP HANA installation procedure. Please take a look at Configuring RHEL 8 for SAP HANA2 installation for information on how to install and configure RHEL 8 for running SAP HANA on each HA cluster node and refer to the SAP HANA Installation guide and the guidelines from the hardware vendor/cloud provider for installing the SAP HANA instances.
The setup described in this document was done using on-premise 'bare-metal' servers. If you plan to use such a setup on a public cloud environment like AWS, Azure or GCP, please check the documentation for the specific platform: HA Solutions for 'performance optimized' SAP HANA Scale-Up System Replication- Configuration Guides.
1.1. Support policies
Please refer to Support Policies for RHEL High Availability Clusters - Management of SAP HANA in a Cluster.
1.2. Required subscription and repositories
As documented in SAP Note 2777782 - SAP HANA DB: Recommended OS Settings for RHEL 8, a RHEL for SAP Solutions subscription is required for every RHEL 8 system running SAP HANA. In addition to the standard repos for running SAP HANA on RHEL 8, all HA cluster nodes must also have the repo for the RHEL HA Add-On enabled. The list of enabled repos should look similar to the following:
[root]# dnf repolist repo id repo name status rhel-8-for-x86_64-appstream-rpms Red Hat Enterprise Linux 8 for x86_64 - AppStream (RPMs) 8,603 rhel-8-for-x86_64-baseos-rpms Red Hat Enterprise Linux 8 for x86_64 - BaseOS (RPMs) 3,690 rhel-8-for-x86_64-highavailability-rpms Red Hat Enterprise Linux 8 for x86_64 - High Availability (RPMs) 156 rhel-8-for-x86_64-sap-solutions-rpms Red Hat Enterprise Linux 8 for x86_64 - SAP Solutions (RPMs) 10
