Placing LifeKeeper Protected Resources in Maintenance Mode During SAP Software Update
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:
- Open the LifeKeeper GUI.
- Right-click the SAP ASCS or SCS resource in each hierarchy on the node where it is currently in-service and click SSHCC HA Actions.
- Select Maintenance Mode in the drop-down box.
- 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: 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.
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=<A/SCS Resource Tag> --cluster
where <A/SCS Resource Tag> is the LifeKeeper tag of the SAP ASCS or SCS resource (e.g., SAP-SID_ASCS00). The output will show whether maintenance mode is fully enabled, partially enabled, or fully disabled for the hierarchy containing the given resource.
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