SAP Maintenance Mode

Placing LifeKeeper Protected Resources in Maintenance Mode During SAP Software Update

*See Maintaining a LifeKeeper Protected System for general steps when performing physical maintenance on a LifeKeeper-protected server.

LifeKeeper has the ability to place the resources in an SAP hierarchy into maintenance mode to allow the user to upgrade their SAP software in-place without having to first bring the hierarchy in-service on a backup server.

When maintenance mode is enabled for the SAP hierarchy:

• Resource health monitoring, local recovery, and failover are disabled for all resources in the hierarchy.

*Note: To minimize the potential for data corruption during the upgrade process, SCSI reservation errors will still be detected and acted on by LifeKeeper. This may cause a resource hierarchy failover or may halt the system in the case of a lost SCSI reservation. To modify the behavior of LifeKeeper when a SCSI device cannot be accessed, see the SCSIERROR parameter in the Core Parameters List.

*Note: When using Quorum/Witness features, the default behavior of LifeKeeper is to halt the node upon loss of quorum. This is beneficial if the user has critical application hierarchies for which a loss of quorum needs to be acted on, but could possibly lead to an unexpected halt while performing maintenance activities if a network communication error occurs. Steps to manually disable/enable Quorum/Witness features can be found on the Quorum/Witness documentation page.

• Any DataKeeper mirrors in the hierarchy will be paused until either maintenance mode is disabled or the user manually resumes the mirror.

*Note: It is not recommended to manually resume any mirror while maintenance mode is enabled for the hierarchy. Since health monitoring, local recovery, and failover are disabled, any failure of the mirror will not be acted on by LifeKeeper.

To place the SAP hierarchies into maintenance mode:

1. Open the LifeKeeper GUI.
2. Right-click each SAP resource on the node where it is currently in-service and click SSHCC HA Actions.

3. Select Maintenance Mode in the drop-down box.

4. Select Enable or Disable maintenance mode for all resources in the chosen hierarchy. This action will be attempted on all nodes in the cluster.

*Note: Maintenance mode is enabled or disabled at the hierarchy level, so maintenance mode must be enabled or disabled for each independent SAP resource hierarchy (e.g., the A/SCS and ERS hierarchies) separately.

*Note: In SAP kernel 7.49 PL 200 and later, placing the SAP software into maintenance mode via SAP Update Manager will automatically place the corresponding LifeKeeper SAP hierarchy into maintenance mode via the HA connector function HASetMaintenanceMode as long as the SAP SIOS HA Cluster Connector is active for the SAP instance. If LifeKeeper resources are placed into maintenance mode manually via the LifeKeeper GUI, the user will need to refer to the documentation for SAP Update Manager to determine how to place the SAP software itself into maintenance mode before upgrading.

Enabling and Disabling SAP Maintenance Mode from the Command Line

To enable SAP Maintenance Mode for all resource hierarchies on all servers in the cluster, execute the following command on one of the servers that is hosting LifeKeeper-protected SAP resources:

sudo /opt/LifeKeeper/lkadm/subsys/appsuite/sap/bin/lk_maintenance_mode --mode=enable --cluster

The optional --tag parameter may also be used to specify that only particular resource hierarchies should be placed into maintenance mode. For example, to place only the (A)SCS and ERS resource hierarchies into maintenance mode, execute the following command on one of the servers that is hosting LifeKeeper-protected SAP resources:

sudo /opt/LifeKeeper/lkadm/subsys/appsuite/sap/bin/lk_maintenance_mode --mode=enable --tag=<A/SCS Resource Tag>,<ERS Resource Tag> --cluster

To disable SAP Maintenance Mode for all resources hierarchies on all servers in the cluster, execute the following command on one of the servers that is hosting LifeKeeper-protected SAP resources:

sudo /opt/LifeKeeper/lkadm/subsys/appsuite/sap/bin/lk_maintenance_mode --mode=disable --cluster

As described above, the optional --tag parameter may also be used to disable maintenance mode for specific resource hierarchies. For example:

sudo /opt/LifeKeeper/lkadm/subsys/appsuite/sap/bin/lk_maintenance_mode --mode=disable --tag=<A/SCS Resource Tag>,<ERS Resource Tag< --cluster

Checking Maintenance Mode Status for LifeKeeper Protected Resources

The LifeKeeper GUI does not currently show the maintenance mode status for each resource hierarchy. To check the maintenance mode status of an SAP hierarchy in LifeKeeper, run the following command from the command line:

sudo /opt/LifeKeeper/lkadm/subsys/appsuite/sap/bin/lk_maintenance_mode --mode=check --tag=<Resource Tag> --cluster

where <Resource Tag> is the LifeKeeper tag of the SAP resource (e.g., SAP-SID_ASCS00 or SAP-SID_ERS10). The output will show whether maintenance mode is fully enabled, partially enabled, or fully disabled for the hierarchy containing the given resource.