Database Reference
In-Depth Information
Chapter 2
Clusterware Stack Management
and Troubleshooting
by Syed Jaffar Hussain, Kai Yu
In Chapter 1, we mentioned that the Oracle RAC cluster database environment requires cluster manager software
(“Clusterware”) that is tightly integrated with the operating system (OS) to provide the cluster management functions
that enable the Oracle database in the cluster environment.
Oracle Clusterware was originally introduced in Oracle 9i on Linux with the original name Oracle Clusterware
Management Service. Cluster Ready Service (CRS) as a generic cluster manager was introduced in Oracle 10.1 for all
platforms and was renamed to today's name, Oracle Clusterware, in Oracle 10.2. Since Oracle 10g, Oracle Clusterware
has been the required component for Oracle RAC. On Linux and Windows systems, Oracle Clusterware is the only
clusterware we need to run Oracle RAC, while on Unix, Oracle Clusterware can be combined with third-party
clusterware such as Sun Cluster and Veritas Cluster Manager.
Oracle Clusterware combines a group of servers into a cluster environment by enabling communication between
the servers so that they work together as a single logical server. Oracle Clusterware serves as the foundation of the
Oracle RAC database by managing its resources. These resources include Oracle ASM instances, database instances,
Oracle databases, virtual IPs (VIPs), the Single Client Access Name (SCAN), SCAN listeners, Oracle Notification
Service (ONS), and the Oracle Net listener. Oracle Clusterware is responsible for startup and failover for the resources.
Because Oracle Clusterware plays such a key role in the high availability and scalability of the RAC database,
the system administrator and the database administrator should pay careful attention to its configuration and
management.
This chapter describes the architecture and complex technical stack of Oracle Clusterware and explains how
those components work. The chapter also describes configuration best practices and explains how to manage and
troubleshoot the clusterware stack. The chapter assumes the latest version of Oracle Clusterware 12cR1.
The following topics will be covered in this chapter:
•
Oracle Clusterware 12cR1 and its components
•
Clusterware startup sequence
•
Clusterware management
•
Troubleshooting cluster stack startup failure
•
CRS logs and directory structure
•
RACcheck, diagcollection.sh, and oratop
•
Debugging and tracing CRS components
•
RAC database hang analysis
