Managing Serviceguard Extension for SAP, December 2007

Step-by-Step Cluster Conversion
SAP Preparation
Chapter 3 85
NOTE For Java-only based installations the only possible installation option is
a High Availability System installation.
It is strongly recommended to use the “High Availability System” option
for all new installations that are meant to be used with SGeSAP.
A SAP Application Server 7.0 may consist of any combination of the
following components:
• Java System Central Services Instance (SCS) [Java Message and
Enqueue Server]
• ABAP System Central Services Instance (ASCS) [ABAP Message and
Enqueue Server]
• Dialog Instance(s) (D, JD, DVEBMGS) [ABAP and/or Java stack]
The potential SPOFs are the SCS, ASCS and DB instances. The Dialog
instance can be installed redundantly on nodes inside or outside the
cluster. The ABAP Central Instance for Netweaver 2004s is similar to a
simple Dialog Instance, except that it is preconfigured to contain the
services Batch, Update, Spool and Gateway. For JAVA, a Central
Instance runs the Java Software Deployment Manager (SDM). These
services though can be also configured redundantly with other Dialog
Instances.
The SAP Netweaver 2004s CDs/DVDs must be available either as
physical copies or images on the local or shared file system for the
duration of the installation.
As preparation, simple Serviceguard packages for the clustered
instances have to be created. They provide the virtual IP addresses that
are required during installation. The package(s) will later on be altered
to become SGeSAP packages. It will be more convenient to do this once
the SAP installation has taken place. The following steps are performed
as root user to prepare the cluster for the SAP installation.