Chapter 2. Planning the HA cluster setup

The solutions for SAP HANA in a Pacemaker cluster for High Availability (HA) are provided in dedicated repositories. The RHEL for SAP Solutions subscription is required to access all relevant content. This subscription includes the RHEL HighAvailability repository.

The <arch> denotes the specific hardware architecture:

Example list of repositories enabled as part of the RHEL for SAP Solutions subscription:

dnf repolist

[root]# dnf repolist
Updating Subscription Management repositories.
repo id                                     repo name
rhel-9-for-x86_64-appstream-e4s-rpms        Red Hat Enterprise Linux 9 for x86_64 - AppStream - Update Services for SAP Solutions (RPMs)
rhel-9-for-x86_64-baseos-e4s-rpms           Red Hat Enterprise Linux 9 for x86_64 - BaseOS - Update Services for SAP Solutions (RPMs)
rhel-9-for-x86_64-highavailability-e4s-rpms Red Hat Enterprise Linux 9 for x86_64 - High Availability - Update Services for SAP Solutions (RPMs)
rhel-9-for-x86_64-sap-netweaver-e4s-rpms    Red Hat Enterprise Linux 9 for x86_64 - SAP NetWeaver - Update Services for SAP Solutions (RPMs)
rhel-9-for-x86_64-sap-solutions-e4s-rpms    Red Hat Enterprise Linux 9 for x86_64 - SAP Solutions - Update Services for SAP Solutions (RPMs)

Check the SAP Note 3108302 - SAP HANA DB: Recommended OS Settings for RHEL 9 for information about minimum Linux kernel versions and other SAP HANA requirements on the OS level.

Deploy your host OS as described in Installing RHEL 9 for SAP Solutions.

Root privileges

For the HANA installation and the cluster HA setup the root user or a privileged user that can execute any sudo commands is required.

You can find information about the sizing of your SAP HANA database in the SAP HANA Master Guide.

For the setup of a scale-up SAP HANA environment with HANA system replication between two nodes, you must make sure that both systems are equipped with the same size of filesystem space for your HANA database. Plan the required space for local database backup files and log segments in accordance with your specific HANA configuration.

You can find information about SAP HANA network architecture considerations in the SAP HANA Administration Guide.

For the SAP HANA system replication setup in a HA cluster we recommend that you configure dedicated networks and connections for the cluster communication traffic, which is separate from any HANA network traffic.

Fencing

For a supported HA cluster setup using the RHEL HA Add-on you must configure a fencing or STONITH device on each cluster node. Which fencing or STONITH device you can use depends on the platform the cluster is running on. Check the Support Policies for RHEL High Availability Clusters - Fencing/STONITH for recommendations on fencing agents or consult your hardware or cloud provider to find out which fence device is supported on their platform.

Quorum

In general, a quorum device is recommended for clusters with an even number of nodes. Two-node clusters specifically have an internal mechanism that handles split-brain situations by itself. For this case a quorum device is optional. Using a quorum device allows the cluster to better determine which node survives in a split-brain situation.

The options for setting up quorum devices vary depending on the platform, infrastructure and configuration.

The sap-hana-ha package provides the combined resource agents which support setups with SAP HANA 2.0 SPS05 rev 59.04 or newer.

To prepare the HANA setup you can define a list of parameters that you require for the installation and configuration of the planned environment.