Using Serviceguard Extension for RAC, 6th Edition, April 2008

version of Serviceguard for up-to-date information at http://www.docs.hp.com
-> High Availability -> Serviceguard.
Overview of SGeRAC and Oracle 10g RAC
Starting with Oracle 10g RAC, Oracle has bundled its own cluster software. The initial
release is called Oracle Cluster Ready Service (CRS). CRS is used both as a generic term
referring to the Oracle cluster software and as a specific term referring to a component
within the Oracle clusters software. At subsequent release, Oracle generic CRS is renamed
to Oracle Clusterware. Oracle Clusterware is the generic term referring to the Oracle Cluster
Software.
The Oracle Cluster Software includes the following components: Cluster Synchronization
Services (CSS), Cluster Ready Service (CRS), and Event Management (EVM).
CSS manages the Oracle cluster membership and provides its own group membership
service to RAC instances. When installed on a SGeRAC cluster, CSS utilizes the group
membership service provided by SGeRAC.
CRS manages Oracle's cluster resources based on configuration, including start, stop,
and monitor, and failover of the resources.
EVM publishes events generated by CRS and may run scripts when certain events
occur.
When installed on a SGeRAC cluster, both the Oracle cluster software and RAC can
continue to rely on the shared storage capability, networking monitoring, as well as
other capabilities provided through Serviceguard and SGeRAC.
Oracle 10g RAC uses the following two subnets for cluster communication purposes:
• CSS Heartbeat Network (CSS-HB): Oracle Clusterware running on the various
nodes of the cluster communicate among themselves using this network.
• RAC Cluster Interconnect Network (RAC-IC): Database instances of a database
use this network to communicate among themselves.
NOTE: In this document, the generic terms “CRS” and “Oracle Clusterware” will
subsequently be referred to as “Oracle Cluster Software”. The use of the term CRS will
still be used when referring to a sub-component of Oracle Cluster Software.
For more detail information on Oracle 10g RAC refer to Chapter 2: “Serviceguard
Configuration for Oracle 10g RAC”.
Overview of SGeRAC Cluster Interconnect Subnet Monitoring
In SGeRAC, the Cluster Interconnect Subnet Monitoring feature is used to monitor
cluster communication subnets. This feature requires the use of a package configuration
parameter known as the CLUSTER_INTERCONNECT_SUBNET. It can be set up to monitor
certain subnets used by applications that are configured as Serviceguard multi-node
packages.
26 Introduction to Serviceguard Extension for RAC