SAP Software Update Manager (SUM)

SUM assumes and requires that your SAP central services are using SAPs sapstartsrv framework.

Before you start a SUM operation in an SAP high availability environment, you must carefully plan this change. The reason is that the SUM procedure involves certain steps (for example, stop and restart SAP instances). These SUM actions might interfere with the automation product that tries to keep the SAP components available always.

The simplistic approach to avoid any interference is to disable automation for all SAP components of the SAP system that SUM needs to stop or (re)start. The disadvantage of this approach is that for the complete elapsed time of the SUM operation you lose your capability to automatically recover from unplanned outages.

Therefore, the recommended way - which allows you to maintain the highest level of availability for your SAP components - is to use the SAP HA Interface as described in SAP HA Interface for SA z/OS. This interface enables seamless interaction between SAP’s management actions (start or stop) and IBM Z System Automation. The SUM processing has a downtime in the EXECUTION phase, which can be reduced by selecting nZDM (near Zero Downtime Maintenance) or ZDO (Zero Downtime Option). Using the SAP HA Interface keeps your system highly available before and after this phase. Note that the SAP shadow and upgrade (ZDO) subsystems which SUM creates and uses internally, are not part of the automation policy. Therefore, SA z/OS does not start, stop, or monitor these subsystems.

Scenario 1: SAP central services that are automated via SA z/OS - no automation for SAP Application servers: If your SAP central services instances are automated via SA z/OS, then you only need to install and activate the SAP HA Interface for SA z/OS. During its operation, SUM performs a stop and a restart of the central services instance. The SAP HA Interface makes sure that SA z/OS votes are inserted to stop the instance and that the votes are removed afterward to restart the instance.

Maintenance Mode: Starting with SUM 1.0 SP 20, SAP has introduced a maintenance mode feature into the SAP HA Interface. The SAP HA Interface can be told that maintenance mode must be switched on (= deactivation of HA solution) or switched off (= activation of HA solution) for an instance or the entire SAP system (without the database).

This maintenance mode is used by the Software Update Manager (SUM) to reduce the need for manual actions. During the preparation of the downtime, the maintenance mode can be activated by the selecting the Use of Maintenance Mode checkbox. Refer to SAP Note 2464065: Check of automatic maintenance mode for HA solutions.

For the prerequisites for SA z/OS see SAP Note 2637199: DB2-z/OS: SUM and HAlib Maintenance Mode on z/OS USS.

Scenario 2: - SAP central services and SAP application servers that are automated via SA z/OS: For the SAP central services, the same recommendation as in scenario 1 applies. For the SAP application servers, you have two options:

• Disable the automation for the SAP either by suspending, or by setting the automation flag to NO for the SAP<SID>RMn_X resources. You lose the application server restart capability of the SA z/OS policy at run time of SUM, but this may be an acceptable risk. Make sure that you enable automation for the remote application server resource again after SUM has finished.
• Install the remote SAP HA Interface for SA z/OS. SA z/OS restarts application server instances if an unplanned outage is detected. When SUM restarts application server instances as part of its normal operation, then SA z/OS votes are inserted and removed again when restarting the instance. You must have installed and activated version 2.0 or higher of the remote SAP HA Interface for SA z/OS for all application servers.