1 Introduction to Installing and Configuring Oracle Database 10g RAC

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.

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.

For Oracle Database 10g requirements, Oracle's clusterware provides equivalent functionality to vendor clusterware while simplifying installation and reducing support complications. However, vendor clusterware may be needed if you use a non-ethernet interconnect or if you have deployed clusterware-dependent applications on the same cluster where you deploy RAC.

On Solaris systems, RAC databases on the same cluster must all be 64-bit, as in Oracle Database 10g and Oracle9i Database, or all be 32-bit, as in Oracle9i Database and Oracle8i Database. A mix of 32-bit RAC databases and 64-bit RAC databases on the same cluster is not supported.

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

The platform-specific 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 9, "Installing Cluster Ready Services on UNIX" and Chapter 10, "Installing Cluster Ready Services on Windows". 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 11, "Installing Oracle Database 10g with Real Application Clusters". You use the OUI in this phase to install the RAC software. Chapter 11, "Installing Oracle Database 10g with Real Application Clusters". The procedures in Chapter 11 are generic for all platforms.

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 (10.1). 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 12, "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 13, "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.

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's Oracle home.

Benefits of Oracle 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.

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:

The Cluster Ready Services Clusterware

The OUI installs CRS on each node on which the OUI detects that vendor clusterware 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. In addition:

• You may use vendor clusterware for all operating systems except Mac OS X and Linux.

• For SunClusters, Oracle provides a UDLM patch that you must install onto each node in the cluster from the /racpatch directory on the Oracle Cluster Ready Services Release 1 CD-ROM before installing and configuring RAC. Although you may have an operative pre-Oracle 10g version of the UDLM, you must install the Oracle 10g UDLM.

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.