Chapter 5. Maintenance procedures
5.1. Updating the OS and HA cluster components
Please refer to Recommended Practices for Applying Software Updates to a RHEL High Availability or Resilient Storage Cluster, for more information.
5.2. Updating the SAP HANA instances
If the SAP HANA System Replication setup is managed using the HA cluster configuration described in this document, some additional steps are needed in addition to the actual process of updating the SAP HANA instances before and after the update. Execute the following steps:
Put the SAPHana resource in unmanaged mode.
[root]# pcs resource unmanage SAPHana_RH1_02-clone
- Update the SAP HANA instances using the procedure provided by SAP.
When the update of the SAP HANA instances has been completed and it has been verified that SAP HANA System Replication is working again, the status of the SAPHana resource needs to be refreshed to make sure the cluster is aware of the current state of the SAP HANA System Replication setup.
[root]# pcs resource refresh SAPHana_RH1_02-clone
When the HA cluster has correctly picked up the current status of the SAP HANA System Replication setup, put the SAPHana resource back into managed mode so that the HA cluster will be able to react to any issues in the SAP HANA System Replication setup again.
[root]# pcs resource manage SAPHana_RH1_02-clone
5.3. Manually moving SAPHana resource to another node (SAP HANA System Replication takeover by HA cluster)
A manual takeover of SAP HANA System Replication can be triggered by moving the promotable clone resource:
[root]# pcs resource move SAPHana_RH1_02-clone
pcs-0.10.8-1.el8 or later is required for this command to work correctly. Please refer to The pcs resource move command fails for a promotable clone unless "--master" is specified, for more information.
With each pcs resource move command invocation, the HA cluster creates a location constraint to cause the resource to move. Please refer to Is there a way to manage constraints when running pcs resource move?, for more information. This constraint must be removed after it has been verified that the SAP HANA System Replication takeover has been completed in order to allow the HA cluster to manage the former primary SAP HANA instance again.
To remove the constraint created by pcs resource move, use the following command:
[root]# pcs resource clear SAPHana_RH1_02-clone
What happens to the former SAP HANA primary instance after the takeover has been completed and the constraint has been removed depends on the setting of the AUTOMATED_REGISTER parameter of the SAPHana resource:
-
If
Automated_REGISTER=true, then the former SAP HANA primary instance will be registered as the new secondary and SAP HANA System Replication will become active again. -
If
AUTOMATED_REGISTER=false, then it is up to the operator to decide what should happen with the former SAP HANA primary instance after the takeover.
