Chapter 3. Installing SAP application server instances

The local directories and mount points required by the SAP instance must be created on the HA cluster node where the (A)SCS instance will be installed:

/sapmnt/
/usr/sap/
/usr/sap/SYS/
/usr/sap/trans/
/usr/sap/S4H/ASCS20/

The shared directories and the instance directory must be manually mounted before starting the installation.

Also, the virtual IP address for the (A)SCS instance must be enabled on node 1, and it must have been verified that the virtual hostname for the ERS instance resolves to the virtual IP address.

When running the SAP installer, please make sure to specify the virtual hostname that should be used for the (A)SCS instance:

[root@node1]# ./sapinst SAPINST_USE_HOSTNAME=s4ascs

Select the High-Availability System option for the installation of the (A)SCS instance:

The local directories and mount points required by the SAP instance must be created on the HA cluster node where the ERS instance will be installed:

/sapmnt/
/usr/sap/
/usr/sap/SYS/
/usr/sap/trans/
/usr/sap/S4H/ERS29

The shared directories and the instance directory must be manually mounted before starting the installation.

Also, the virtual IP address for the ERS instance must be enabled on node 2, and it must have been verified that the virtual hostname for the ERS instance resolves to the virtual IP address.

Make sure to specify the virtual hostname for the ERS instance when starting the installation:

[root@node2]# ./sapinst SAPINST_USE_HOSTNAME=s4ers

Select the High-Availability System option for the installation of the ERS instance:

The local directories and mount points required by the SAP instance must be created on the HA cluster node where the primary or additional application server instance(s) will be installed:

/sapmnt/
/usr/sap/
/usr/sap/SYS/
/usr/sap/trans/
/usr/sap/S4H/
/usr/sap/S4H/D<Ins#>

The shared directories and the instance directory must be manually mounted before starting the installation.

Also, the virtual IP address for the application server instance must be enabled on the HA cluster node, and it must have been verified that the virtual hostname for the application server instance resolves to the virtual IP address.

Specify the virtual hostname for the instance when starting the installer:

[root@node<X>]# ./sapinst SAPINST_USE_HOSTNAME=<virtual hostname of instance>

Select the High-Availability System option for the installation of the application server instance.

The (A)SCS instance profile has to be modified to prevent the automatic restart of the enqueue server process by the sapstartsrv process of the instance, since the instance will be managed by the cluster. 

To modify the (A)SCS instance profile, run the following command:

[root@node1]# sed -i -e 's/Restart_Program_01/Start_Program_01/' /sapmnt/S4H/profile/S4H_ASCS20_s4ascs

The ERS instance profile has to be modified to prevent the automatic restart of the enqueue replication server process by the sapstartsrv of the instance since the ERS instance will be managed by the cluster. 

To modify the ERS instance profile, run the following command:

[root@node2]# sed -i -e 's/Restart_Program_00/Start_Program_00/' /sapmnt/S4H/profile/S4H_ERS29_s4ers

To prevent the SAP instances that will be managed by the HA cluster to be started outside of the control of the HA cluster, make sure the following lines are commented out in the /usr/sap/sapservices file on all cluster nodes:

#LD_LIBRARY_PATH=/usr/sap/S4H/ERS29/exe:$LD_LIBRARY_PATH; export LD_LIBRARY_PATH; /usr/sap/S4H/ERS29/exe/sapstartsrv pf=/usr/sap/S4H/SYS/profile/S4H_ERS29_s4ers -D -u s4hadm

#LD_LIBRARY_PATH=/usr/sap/S4H/ASCS20/exe:$LD_LIBRARY_PATH; export LD_LIBRARY_PATH; /usr/sap/S4H/ASCS20/exe/sapstartsrv pf=/usr/sap/S4H/SYS/profile/S4H_ASCS20_s4ascs -D -u s4hadm

#LD_LIBRARY_PATH=/usr/sap/S4H/D21/exe:$LD_LIBRARY_PATH; export LD_LIBRARY_PATH; /usr/sap/S4H/D21/exe/sapstartsrv pf=/usr/sap/S4H/SYS/profile/S4H_D21_s4hpas -D -u s4hadm

#LD_LIBRARY_PATH=/usr/sap/S4H/D22/exe:$LD_LIBRARY_PATH; export LD_LIBRARY_PATH; /usr/sap/S4H/D22/exe/sapstartsrv pf=/usr/sap/S4H/SYS/profile/S4H_D22_s4haas -D -u s4hadm

The mount points where the instance-specific directories will be mounted have to be created and the user and group ownership must be set to the <sid>adm user and the sapsys group on all HA cluster nodes:

[root@node1]# mkdir /usr/sap/S4H/ERS29/
[root@node1]# chown s4hadm:sapsys /usr/sap/S4H/ERS29/

[root@node2]# mkdir /usr/sap/S4H/ASCS20
[root@node2]# chown s4hadm:sapsys /usr/sap/S4H/ASCS20

[root@node<x>]# mkdir /usr/sap/S4H/D<Ins#>
[root@node<x>]# chown s4hadm:sapsys /usr/sap/S4H/D<Ins#>

Stop the (A)SCS and ERS instances using sapcontrol`, unmount the instance specific directories and then mount them on the other node:

/usr/sap/S4H/ASCS20/
/usr/sap/S4H/ERS29/
/usr/sap/S4H/D<Ins#>/

Verify that manual starting and stopping of all SAP instances using sapcontrol works on all HA cluster nodes and that the SAP instances are running correctly using the tools provided by SAP.

Run the following command on each cluster node to verify that SAP Host Agent has the same version and meets the minimum version requirement:

[root@node<x>]# /usr/sap/hostctrl/exe/saphostexec -version

Please check SAP Note 1031096-Installing Package SAPHOSTAGENT in case SAP Host Agent needs to be updated.

To ensure that the SAP instances continue to run after a failover, it might be necessary to install several SAP license keys based on the hardware key of each cluster node. Please see SAP Note 1178686 - Linux: Alternative method to generate a SAP hardware key for more information.

If the SAP instances that will be managed by the cluster are systemd enabled, additional configuration changes are required to ensure that systemd does not interfere with the management of the SAP instances by the HA cluster. Please check out section 2. Red Hat HA Solutions for SAP in The Systemd-Based SAP Startup Framework for information.