Managing Serviceguard Extension for SAP, December 2007

Step-by-Step Cluster Conversion
Chapter 3 83
The SAP Application Server installation types are ABAP-only, Java-only
and Add-in. The latter includes both the ABAP and the Java stack.
In principle all SAP cluster installations look very similar. Older SAP
systems get installed in the same way as they would without a cluster.
Cluster conversion takes place afterwards and includes a set of manual
steps. Some of these steps can be omitted since the introduction of high
availability installation options to the SAP installer SAPINST. In this
case, a part of the cluster configuration is done prior to the SAP
installation as such. The SAP Instances can then be installed into a
virtualized environment, which obsoletes the SAP Application Server
Configuration steps that usually concluded a manual cluster conversion.
Therefore, it is important to first decide which kind of SAP installation is
intended. The installation of a SAP High Availability System was
introduced with Netweaver 2004s. For Netweaver 2004 JAVA-only
installations there is a similar High Availability Option for SAPINST. All
older SAP kernels need to be clustered manually. The SAP preparation
chapter covers all three cases. It also describes how Enqueue Replication
can be activated for use with SGeSAP. The exact steps for that also
depend on the SAP release that gets used.
Other differences in cluster layout derive from the usage of HP
Serviceguard Cluster Filesystem. Alternative setups use HA NFS
packages and automounter technology to ensure cluster-wide access to
filesystems.
Finally, the underlying database of course also causes slightly different
installation steps.