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Oracle® Real Application Clusters Installation and Configuration Guide
10g Release 1 ( for Linux x86-64
Part No. B14406-01
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1 Introduction to Installing and Configuring Oracle Database 10g RAC

This chapter provides an overview of the Real Application Clusters (RAC) installation and configuration procedures and includes the following topics:

Real Application Clusters Documentation Overview

This section describes the RAC documentation set. The Oracle Database 10g CD contains a copy of this book, the Oracle Real Application Clusters Installation and Configuration Guide in both HTML and PDF formats. This book contains the pre-installation, installation, and post-installation information for platform.

The Server Documentation CD contains the following additional documentation about RAC administration and deployment: the Oracle Real Application Clusters Administrator's Guide and the Oracle Real Application Clusters Deployment and Performance Guide as described under the following headings:

Oracle Real Application Clusters Administrator's Guide

The Oracle Real Application Clusters Administrator's Guide provides RAC-specific administration information. Some of the topics described in this book include the use of Oracle Enterprise Manager in RAC environments. The book also describes how to administer services and storage and how to use RAC scalability features to add and delete instances and nodes in RAC environments. The book also discusses how to use Recovery Manager (RMAN) and how to perform backup and recovery in RAC.

The Oracle Real Application Clusters Administrator's Guide also describes how to use the Server Control (SRVCTL) utility to start and stop the database and instances, manage configuration information, and to delete or move instances and services. You can also use the appendix to resolve various RAC tools messages. A troubleshooting section describes how to interpret the content of RAC-specific log files.

Oracle Real Application Clusters Deployment and Performance Guide

The Oracle Real Application Clusters Deployment and Performance Guide highlights the main deployment topics for RAC by briefly describing Cluster Ready Services (CRS), storage, database creation, and services deployment in RAC. Design and deployment topics in this book describe service topologies and workload management in RAC. Specifically, the book describes how the Automatic Workload Repository tracks and reports service levels and how you can use service level thresholds and alerts to improve high availability in your RAC environment. There is also a services deployment example in the appendix of this book that you can use to learn more about how to deploy and manage services in RAC environments.

The Oracle Real Application Clusters Deployment and Performance Guide provides a high-level description of interconnect protocols, as well as information about how to monitor and tune performance in RAC environments using both Oracle Enterprise Manager and using information in the Automated Workload Repository and Oracle performance views. The book also highlights some application-specific deployment techniques for online transaction processing and data warehousing environments.

General System Installation Requirements for Real Application Clusters

Each node that is going to be part of your RAC installation must meet the following hardware and software requirements. You will also perform step-by-step tasks for hardware and software verification for Linux x86-64 specific pre-installation procedures in Part II of this book.

Before using this manual, however, you should read the Oracle Real Application Clusters Deployment and Performance Guide and the Oracle Real Application Clusters Administrator's Guide.

Software Requirements for Oracle Database 10g Real Application Clusters

Each node in a cluster requires a supported interconnect software protocol to support Cache Fusion, and Cluster Ready Services (CRS) polling. Your interconnect must be certified by Oracle for your platform. You should also have a Web browser to enable Oracle Enterprise Manager and to view online documentation.

Cluster Setup and Pre-Installation Configuration Tasks for Real Application Clusters

Before installing RAC, perform the following procedures:

  1. Ensure that you have a certified combination of operating system and Oracle software version by referring to the OracleMetaLink certification information under "Availability & Certification" > "1.View Certifications by Product" at the following site:


    The layout of the MetaLink site and the site's certification policies are subject to change.

  2. Configure a high-speed interconnect that uses a private network. Configure a second interconnect for redundancy, if the interconnect redundancy is supported by the platform, to avoid making the interconnect a single point of failure. Some platforms support automatic failover to the alternate interconnect. To enable this, you must configure the operating system-provided failover mechanism.

  3. Determine the storage option for your system and configure the shared disk. Oracle recommends that you use Automatic Storage Management (ASM) and Oracle Managed Files (OMF), or a cluster file system. If you use ASM or a cluster file system, then you can also take advantage of OMF and other Oracle Database 10g storage features. If you use RAC on the Oracle Database 10g Standard Edition, then you must use ASM.


    If you use ASM, Oracle recommends that you install ASM in a separate home from the CRS home and the Oracle home, particularly if the ASM instance is to manage storage for more than one RAC database. This reduces downtime when upgrading or de-installing different versions of the software. However, you must create the ASM instance manually because the OUI and DBCA do not support a separate install of ASM.

  4. Install the operating system patches that are listed in the pre-installation chapters in this book in Part II.

Pre-Installation, Installation, and Post-Installation Overview

The following describes the installation procedures that are covered in Part II and Part III of this book.

Pre-Installation Overview for Oracle Database 10g Real Application Clusters

The pre-installation procedures in Part II explain how to verify user equivalence, perform network connectivity tests, as well as how to set directory and file permissions. Complete all of the pre-installation procedures and verify that your system meets all of the pre-installation requirements before proceeding to the install phase.

Installation Overview for Oracle Database 10g Real Application Clusters

The Oracle Database 10g Real Application Clusters installation is a two-phase installation. In phase one, use the Oracle Universal Installer (OUI) to install CRS as described in Chapter 3, "Installing Cluster Ready Services on Linux Systems". Note that the Oracle home that you use in phase one is a home for the CRS software which must be different from the Oracle home that you use in phase two for the installation of the Oracle database software with RAC components. The CRS pre-installation starts the CRS processes in preparation for installing Oracle Database 10g with RAC as described in Chapter 4, "Installing Oracle Database 10g with Real Application Clusters". You use the OUI in this phase to install the RAC software.

If the OUI detects Oracle cluster software from a previous release, then the OUI starts the Database Upgrade Assistant (DBUA) to upgrade your database to Oracle Database 10g release 1 ( In addition, the DBUA displays a Service Configuration page for configuring services in your RAC database.

After the installation completes, the OUI starts the Oracle assistants, such as the DBCA, to configure your environment and create your RAC database. You can later use the DBCA Instance Management feature to add or modify services and instances as described in Chapter 5, "Creating RAC Databases with the Database Configuration Assistant".

Post-Installation Overview for Oracle Database 10g Real Application Clusters

After you create your database, download and install the most recent patch sets for your Oracle Database 10g version as described in Chapter 6, "Real Application Clusters Post-Installation Procedures". If you are using other Oracle products with your RAC database, then you must also configure them.

You must also perform several post-installation configuration tasks to use certain Oracle Database 10g products such as the Sample Schema, Oracle Net Services, or Oracle Messaging Gateway. You must also configure Oracle pre-compilers for your operating system and if desired, configure Oracle Advanced Security.

Use the Companion CD to install additional Oracle Database 10g software that may improve performance or extend database capabilities, for example, Oracle JVM, Oracle interMedia or Oracle Text.

See Also:

Oracle Real Application Clusters Administrator's Guide for more information about using RAC scalability features of adding and deleting nodes and instances from RAC databases

The Oracle Universal Installer and Real Application Clusters

The Oracle Universal Installer (OUI) facilitates the installation of Cluster Ready Services (CRS) and Oracle Database 10g software. In most cases, you use the graphical user interface (GUI) provided by the OUI to install the software. However, you can also use the OUI to complete non-interactive installations, without using the GUI. See Appendix B for information about non-interactive installations.

When the OUI installs the Oracle software, Oracle recommends that you select a preconfigured database or use the Database Configuration Assistant (DBCA) interactively to create your cluster database. You can also manually create your database as described in procedures posted at Oracle recommends that you use Automatic Storage Management (ASM). If you are not using ASM or if you are not using a cluster file system, then configure shared raw devices before you create your database.

When you install CRS or RAC, the OUI copies the Oracle software onto the node from which you are running it. If your Oracle home is not on a cluster file system, then the OUI propagates the software onto the other nodes that you have selected to be part of your OUI installation session.

When you create your RAC database using the OUI, or if you do it later using the DBCA, or if you use the Enterprise Manager Configuration Assistant to configure Enterprise Manager, Enterprise Manager is configured for your cluster database. Database control can manage your RAC database, all of its instances, and the hosts where instances are configured.

You can also configure Enterprise Manager Grid Control to manage multiple databases and application servers from a single console. To manage RAC databases in Grid Control, you must install a Grid Control agent on each of the nodes of your cluster. The Agent installation is clusterized, which means you need to perform the install on only one of the cluster nodes.

See Also:

  • The Oracle Universal Installer Concepts Guide for more details about the OUI

  • The Oracle Real Application Clusters Administrator's Guide for information about using Enterprise Manager to administer RAC environments

Storage Considerations for Installing Oracle Database 10g Real Application Clusters

Oracle recommends using Automatic Storage Management (ASM) or a cluster file system with Oracle Managed Files (OMF) for database storage. This section provides an overview of ASM.

Note that RAC installations using the Oracle Database Standard Edition must use ASM for database file storage.

Overview of Automatic Storage Management

You can use ASM to simplify the administration of Oracle database files. Instead of having to manage potentially thousands of database files, using ASM, you need to manage only a small number of disk groups. A disk group is a set of disk devices that ASM manages as a single logical unit. You can define a particular disk group as the default disk group for a database, and Oracle will automatically allocate storage for, create, or delete, the files associated with the appropriate database object. When administering the database, you need only refer to database objects by name, rather than by file name.

When using ASM with a single Oracle home for database instances on a node, the ASM instance can run from that same home. If you are using ASM with Oracle database instances from multiple database homes on the same node, then Oracle recommends that you run the ASM instance from an Oracle home that is distinct from the database homes. In addition, the ASM home should be installed on every cluster node. This prevents the accidental removal of ASM instances that are in use by databases from other homes during the de-installation of a database Oracle home.

Benefits of Automatic Storage Management

ASM provides many of the same benefits as storage technologies such as RAID or logical volume managers (LVMs). Like these technologies, ASM enables you to create a single disk group from a collection of individual disk devices. It balances I/O to the disk group across all of the devices in the disk group. It also implements striping and mirroring to improve I/O performance and data reliability.

However, unlike RAID or LVMs, ASM implements striping and mirroring at the file level. This implementation enables you to specify different storage attributes for individual files in the same disk group.

Disk Groups and Failure Groups

A disk group can include any number of disk devices. Each disk device can be an individual physical disk, a multiple disk device such as a RAID storage array or logical volume, or even a partition on a physical disk. However, in most cases, disk groups consist of one or more individual physical disks. To enable ASM to balance I/O and storage appropriately within the disk group, all devices in the disk group should have similar, if not identical, storage capacity and performance.


Do not specify more than one partition on a single physical disk as a disk group device. ASM expects each disk group device to be on a separate physical disk.

Although you can specify a logical volume as a device in an ASM disk group, Oracle does not recommend their use. Because logical volume managers can hide the physical disk architecture, ASM may not operate effectively when logical volumes are specified as disk group devices.

When you add a device to a disk group, you can specify a failure group for that device. Failure groups identify disk devices that have common failure characteristics, for example, devices that are attached to the same controller. If the controller fails, then all devices attached to it become unavailable. By default, each device also belongs to its own failure group. By using the failure groups you specify, ASM can distribute data among the devices in the disk group to help minimize the risk of data loss caused by component failures.

Redundancy Levels

ASM provides three levels of mirroring, called redundancy levels, that you can specify when creating a disk group. The redundancy levels are:

  • External redundancy

    In disk groups created with external redundancy, the contents of the disk group are not mirrored by ASM. You might choose this redundancy level when:

    • The disk group contains devices, such as RAID devices, that provide their own data protection

    • Your use of the database does not require uninterrupted access to data, for example, in a development environment where you have a suitable back-up strategy

  • Normal redundancy

    In disk groups created with normal redundancy, the contents of the disk group are two-way mirrored by default. However, you can choose to create certain files that are not mirrored. To create a disk group with normal redundancy, you must specify at least two failure groups (a minimum of two devices).

    The effective disk space of a disk group that uses normal redundancy is half the total disk space of all of its devices.

  • High redundancy

    In disk groups created with high redundancy, the contents of the disk group are three-way mirrored by default. However, you can choose to create certain files that are only two-way mirrored, or that are not mirrored. To create a disk group with high redundancy, you must specify at least three failure groups (a minimum of three devices).

    The effective disk space of a disk group that uses high redundancy is one-third of the total disk space of all of its devices.

ASM and Installation Types

The type and number of disk groups that you can create when installing Oracle software depends on the type of database you choose to create during the installation, as follows:

  • Preconfigured database

    If you choose to create the default preconfigured database that uses ASM, the OUI prompts you to specify two disk device names, which it uses to create a disk group named DATA, with normal redundancy.

  • Advanced database

    If you choose to create an advanced database that uses ASM, you can create one or more disk groups. These disk groups can use one or more devices. For each disk group, you can specify the redundancy level that suits your requirements.

The following table lists the total disk space required in all disk group devices for a typical preconfigured database, depending on the redundancy level you choose to use for the disk group:

Redundancy Level Total DIsk Space Required
External 1 GB
Normal 2 GB (on a minimum of two devices)
High 3 GB (on a minimum of three devices)

Additional Considerations for Using Oracle Database 10g Features in RAC

Oracle recommends using the following Oracle Database 10g features to simplify RAC database management:

Oracle Database 10g and Real Application Clusters Components

Oracle Database 10g provides single-instance database software and the additional components to operate RAC databases. Some of the RAC-specific components include:

The Cluster Ready Services Clusterware

The OUI installs CRS on each node on which the OUI detects that Oracle9i cluster manager is present. If vendor clusterware is not present, then you must use the OUI to enter the nodes on which to install CRS. The CRS home can be either shared by all nodes or private to each node depending on your responses when you run the OUI. The home that you select for CRS must be different from the RAC-enabled Oracle home.

When vendor clusterware is present, CRS interacts with the vendor clusterware to coordinate cluster membership information. For Oracle Database 10g on Linux, CRS coexists with but does not interact with previous Oracle clusterware versions.


On Linux, pre-Oracle Database 10g cluster manager implementations were referred to as "Cluster Manager". In Oracle Database 10g, the cluster manager role is performed by Cluster Synchronization Services (CSS), a component of CRS. The OCSSD performs this function.

The Installed Real Application Clusters Components

All instances in RAC environments share the control file, server parameter file, redo log files, and all datafiles. These files reside on a shared cluster file system or on shared disks. Either of these types of file configurations are accessed by all the cluster database instances. Each instance also has its own set of redo log files. During failures, shared access to redo log files enables surviving instances to perform recovery.

Oracle Database 10g Real Application Clusters Version Compatibility

You can install and operate different versions of Oracle cluster database software on the same computer as described in the following points:

Required UNIX Groups

This section describes information specific to RAC on UNIX-based platforms. Depending on whether this is the first time you are installing the Oracle server software on your Linux system, you may need to create several UNIX groups and a UNIX user as described later in the pre-installation procedures. The required UNIX groups and user are:

A single Oracle Inventory group is required for all installations of Oracle software on the system. However, you can create different Oracle software owner users, OSDBA groups, and OSOPER groups (other than oracle, dba, and oper) for separate installations. Using different groups enables you to grant DBA privileges to a particular operating system user on one database, which they would not have on another database on the same system.

See Also:

The Oracle Database Administrator's Reference, 10g Release 1 (10.1) for UNIX Systems and the Oracle Database 10g Administrator's Guide contain more information about the OSDBA and OSOPER groups and the SYSDBA and SYSOPER privileges.