User's Guide

1 Designing SGeSAP Cluster Scenarios
This chapter introduces the basic concepts used by the HP Serviceguard Extension for SAP (SGeSAP) and
explains several naming conventions. The following sections provide recommendations and examples for
typical cluster layouts that can be implemented for SAP environments:
• General Concepts of SGeSAP
• Mutual Failover Scenarios Using the Two Package Concept
• One Package Concept
• Follow-and-Push Clusters with Replicated Enqueue
• Dedicated NFS Packages
• Dialog Instance Clusters as Simple Tool for Adaptive Enterprises
• Handling of Redundant Dialog Instances
• Dedicated Failover Host
General Concepts of SGeSAP
SGeSAP extends HP Serviceguard's failover cluster capabilities to SAP application environments. SGeSAP
continuously monitors the health of each SAP cluster node and automatically responds to failures or threshold
violations. It provides a flexible framework of package templates to easily define cluster packages that protect
various components of a mission-critical SAP infrastructure.
SGeSAP provides a flexible framework of package templates to easily define cluster packages that protect
various components of a mission-critical SAP infrastructure. SGeSAP provides a single, uniform interface to
cluster ABAP-only, JAVA-only, and add-in installations of SAP Web Application Servers (SAP WAS). Support
includes SAP R/3 kernel, mySAP components, SAP Application Server for ABAP, SAP Application Server
for JAVA, and SAP Netweaver based SAP applications in a range of supported release versions as specified
in the separately available release notes.
The clustered SAP components include SAP ABAP Central Services, SAP JAVA Central Services, SAP ABAP
Application Servers, SAP JAVA Application Servers, SAP Central Instances, SAP Enqueue Replication Servers,
Oracle single-instance databases, MAXDB databases, SAP liveCache and SAP MDM components. For some
platforms, support for liveCache hot standby clusters is included.
It is possible to combine all clustered components of a single SAP system into one failover package for
simplicity and convenience. There is also full flexibility to split components up into several packages to avoid
unwanted dependencies and to lower potential failover times.
Multiple SAP applications of different type and release version can be consolidated in a single cluster.
SGeSAP enables SAP instance virtualization. It is possible to use SGeSAP to move redundant SAP ABAP
Application Server Instances between hosts to quickly adapt to changing resource demands or maintenance
needs. SGeSAP allows utilizing a combination of HP 9000 and HP Integrity servers in a mixed cluster with
heterogeneous failover of SAP packages.
SAP applications can be divided into one or more distinct software components. Most of these components
share a common technology layer, the SAP Application Server (SAPWAS). The SAP Application Server is
the central building block of the SAP Netweaver technology. Each Application Server implementation comes
with a characteristic set of software Single Points of Failure. These will become installed across the cluster
hardware according to several high availability considerations and off-topic constraints, resulting in an
individual configuration recommendation.
There are various publications available from SAP and third parties that describe the software components
used by SAP applications in more detail. It is recommended to refer to these documents to get a basic
familiarity before continuing to read. It is also recommended to familiarize with Serviceguard clustering and
virtualization by reading the Serviceguard product manual "Managing Serviceguard", fifteenth edition or
higher. The latest version can always be found at http://docs.hp.com/en/ha.html#Serviceguard .
Serviceguard packages can be distinguished into legacy packages and module-based packages. SGeSAP
provides solutions for both approaches. SGeSAP consists of several SAP-related modules, legacy script
General Concepts of SGeSAP 11