Installation guide

1 Executive Summary

This paper details the deployment of a highly available SAP service on a Red Hat Enterprise

Linux 5 cluster. After an introduction to the basic concepts and system requirements, this

document will provide detailed information about the Red Hat Cluster Suite (RHCS), SAP

NetWeaver, and cluster configuration options.

1.1 Introduction

A cluster is essentially a group of two or more computers working together which, from an end

users perspective, appear as one server. Clustering can be used to enable storage

clustering, balance load among cluster members, parallel processing, and high-availability

(HA). The highly available aspect of any cluster service indicates that it is configured in a

manner such that the failure of any one cluster member, or a subsystem failure within a

member, will not prevent the continued availability of the service itself.

Ensuring the highest possible availability of your SAP systems is essential for success. The

availability of an SAP application typically depends on an SAP application server which in turn

relies on optimal availability of an underlying database. This layered software stack sits atop

an even more complex hardware infrastructure. In order to increase the availability of SAP

software, redundant hardware and additional cluster software is required. The cluster

software monitors the status of services provided by running SAP software and initiates

failover to redundant server infrastructure if problems are detected. RHCS, bundled with Red

Hat Enterprise Linux, provides the features necessary to make critical SAP services highly

available. This document will illustrate the recommended highly available RHCS infrastructure

for SAP.

When configuring HA for an SAP environment, all the software and hardware layers must be

taken into consideration. Red Hat, ATIX and REALTECH , with guidance from SAP, have

conducted development work in order to provide a reference architecture of High Availability

for SAP NetWeaver using RHCS. This implementation is compliant with SAP

recommendations and this document is the result of this partnered development. Together

with the resource scripts in Red Hat Enterprise Linux 5.3, this reference architecture can

serve as a guide to deploying highly available SAP applications (the majority of the SAP

product portfolio including ECC, SCM, SRM, etc.) based upon SAP NetWeaver technology. It

is provided as is without support or liability statements. Experts at the required technologies

may follow this guide when implementing highly available, Red Hat Enterprise Linux based

SAP system(s).

Note that cluster software has full control of all services including the starting and stopping of

SAP software. Numerous customer cases have proven how a poorly configured HA

environment can inadvertently decrease the availability of critical SAP systems. As such,

consulting services familiar with both SAP and RHCS would be a cost effective investment.