How to start/stop a clustered (A)SCS instance in a Windows cluster?
This blog describes how you can start/stop clustered SAP instances in a Windows Failover cluster environment. It also describes how the SAP HA interface behaves from an end user / administrator perspective.
Clustered SAP instances can contain:
- an ASCS instance (message server, enqueue server, optional: gateway and/or Web Dispatcher) for an ABAP system
- or a SCS instance (message server, enqueue server, optional: gateway and/or Web Dispatcher) for a JAVA system
- a standalone gateway (for example, to be used on a database cluster)
- a Web Dispatcher instance
- a clustered enqueue replicator 2 instance (only valid for S/4 configurations, NetWeaver still uses non-clustered enqueue replication server configuration)
This is an example of a S/4 based system, viewed from SAP MMC. The ASCS instance consists of a message server and an enqueue server 2:
The clustered enqueue replicator instance is shown in SAP MMC here:
In Windows Failover Cluster Manager we see that the corresponding cluster resources are online:
Cluster group “SAP RA4” contains the two cluster resources of the RA4 ASCS instance:
The SAP RA4 00 Service resource starts the service. The SAP RA4 00 Instance resource starts the instance.
An administrator triggers the stop of an instance via SAP MMC. The instance stops, the sapstartsrv service remains running:
In Failover Cluster Manager you see:
Only the instance cluster resource has been stopped. The service is still running. All other resources in the cluster group (network related resources, disk / file share related resources …) are still running.
Administrator triggers start of the instance in SAP MMC:
SAP MMC shows “green” = all processes started successfully:
and the Failover Cluster Manager shows the related cluster resource as “online” again:
You can start / stop clustered instances using SAP MMC or the command-line tool “sapcontrol.exe”, or you can use the Failover Cluster Manager tool.
You cannot stop or start non-clustered SAP instances with Failover Cluster Manager, like dialog instances.
If you start / stop a clustered SAP instance via SAP MMC or sapcontrol.exe, but you don’t see a related action in Failover Cluster Manager tool, then permissions in the clusters are missing or misconfigured.
Open Failover Cluster Manager tool, navigate to the name of the cluster and select “Properties”:
Navigate to “Cluster Permissions” tab:
The domain group SAP_<SID>_GlobalAdmin must have full control to control the cluster.