Consolidating HP Serviceguard for Linux and Oracle RAC 10g Clusters, June 2005

Executive Summary

Oracle Real Application Clusters (RAC) 10g Release1 database server includes a clustering

solution that supports Oracle database servers in a highly available environment. Although

this feature eliminates the requirement for a third-party cluster product for the database,

additional components are needed to provide high availability for applications to run on the

same servers that are part of the RAC cluster. HP Serviceguard for Linux can provide

additional value in a RAC cluster by providing high availability for other applications

running on those servers. This raises the question, “With Serviceguard for Linux running on

the same hardware as the Oracle Cluster Ready Services (CRS – RAC’s cluster membership

mechanism), how can the two clusters be kept from interfering with each other?”

This white paper specifies the recommended configurations that will achieve a stable

Serviceguard for Linux and RAC consolidated cluster, with Serviceguard for Linux coexisting

in the RAC clustered database environment. The recommendations to achieve a stable

consolidated cluster setup include multiple heartbeat subnets, redundant heartbeat networks

(by means of channel-bonding), and the optional usage of the Quorum Service as the

arbitration method for Serviceguard for Linux.

Introduction

Many customers have built highly available Oracle database environments on Linux using

the “single instance” version of Oracle and HP Serviceguard for Linux protecting both the

database and application layers. With Oracle 10g Real Application Cluster, database

scalability as well as high availability are built into the clustered product.

Oracle states that the Oracle 10g R1 replaces “the need to purchase, install, configure, and

support third-party cluster software”. In addition, on Linux, Oracle mandates the use of CRS

for RAC and specifies that other clustering software should not be used for deriving cluster

membership For RAC.

This capability does not provide high availability for other

applications.

As a result, when there is a requirement to provide high availability for other

applications in an Oracle RAC environment, customers must use other high availability

cluster software. Before the evaluation and recommendations documented by this white

paper, HP required the applications and database be deployed on separate clusters. As a

result of this evaluation, HP enables customers to lower their Oracle RAC environment costs

by providing high availability encapsulation with HP Serviceguard for Linux for non-RAC

applications running on the same nodes of an Oracle RAC cluster. Even if Oracle

eventually provides failover functionality for third party applications in a RAC environment,

the use of Serviceguard for Linux instead of Oracle RAC cluster is attractive because of its

proven robustness and stability.

This whitepaper provides a set of guidelines for consolidating Serviceguard for Linux with

Oracle 10g RAC clusters on the same server nodes, so as to eliminate any foreseeable

interference between the two clusters in the event of a failure that causes cluster

reconfigurations. The guidelines are based on an investigation where Oracle 10g RAC and

Serviceguard for Linux coexistence was tested for possible failure scenarios.