The ABAP Only Configuration comprises the installation of:
- Central Services Instance for ABAP (ASCS Instance)
- Enqueue Replication Server Instance (ERS Instance) for the ASCS Instance (optional)
- Database Instance (DB Instance)
- Primary Application Server Instance (PAS)
- Additional Application Server Instances (AAS) – It is recommended that Additional Application Server Instances (AAS) be installed on hosts different from the Primary Application Server Instance (PAS) Host
Switchover Cluster for an SAP ABAP Only (ASCS) System
In the above example, ASCS is in a separate LifeKeeper hierarchy from the Database. Although it is active on the same server as the Database, they can fail over separately.