Using Serviceguard Extension for RAC, 9th Edition, September 2010

1 Introduction to Serviceguard Extension for RAC
Serviceguard Extension for RAC (SGeRAC) enables the Oracle Real Application Cluster (RAC),
formerly known as Oracle Parallel Server RDBMS, to run on HP high availability clusters under
the HP-UX operating system. This chapter introduces Serviceguard Extension for RAC and shows
where to find different kinds of information in this book. The following topics are presented:
• “What is a Serviceguard Extension for RAC Cluster? ”
• “Serviceguard Extension for RAC Architecture”
• “Overview of SGeRAC and Cluster File System (CFS)/Cluster Volume Manager (CVM)”
• “Overview of SGeRAC and Oracle 10g, 11gR1, and 11gR2 RAC”
• “Overview of SGeRAC Cluster Interconnect Subnet Monitoring ”
• “Overview of SGeRAC and Oracle 9i RAC”
• “Node Failure”
• “Larger Clusters ”
• “Extended Distance Cluster Using Serviceguard Extension for RAC”
What is a Serviceguard Extension for RAC Cluster?
A high availability cluster is a grouping of HP servers having sufficient redundancy of software
and hardware components that a single point of failure will not disrupt the availability of
computer services. High availability clusters configured with Oracle Real Application Cluster
software are known as RAC clusters. Figure 1-1 shows a very simple picture of the basic
configuration of a RAC cluster on HP-UX.
Figure 1-1 Overview of Oracle RAC Configuration on HP-UX
In the figure, two loosely coupled systems (each one known as a node) are running separate
instances of Oracle software that read data from and write data to a shared set of disks. Clients
connect to one node or the other via LAN.
RAC on HP-UX lets you maintain a single database image that is accessed by the HP servers in
parallel, thereby gaining added processing power without the need to administer separate
What is a Serviceguard Extension for RAC Cluster? 15