3 Creating Oracle Real Application Clusters Databases with Database Configuration Assistant

This chapter describes how to use Database Configuration Assistant (DBCA) in standalone mode to create and delete Oracle Real Application Clusters (Oracle RAC) databases. The topics in this chapter include the following:

Using Database Configuration Assistant with Oracle RAC
Benefits of Using Database Configuration Assistant
Automatic Listener Migration from Earlier Releases
Verifying Requirements for DBCA
Creating an Oracle RAC Database with DBCA
Deleting an Oracle RAC Database with DBCA
Configuring Database Control During Installation

See Also:
Oracle Real Application Clusters Administration and Deployment Guide for procedures on using DBCA to add and delete instances

3.1 Using Database Configuration Assistant with Oracle RAC

DBCA has the following primary database functions:

Create and delete the database
Add and delete database instances
Set up network configuration for the database and its instances
Register the database in Oracle Enterprise Manager Grid Control or configure Database Control
Configure options for the database, such as Oracle Database Vault
Start up the database and its instances

Note:
Cluster Managed Services are no longer managed through DBCA. Instead, use the cluster managed services page in Oracle Enterprise Manager DB Control (accessible from the Cluster Database Availability Page). For more information, refer to Oracle Real Application Clusters Administration and Deployment Guide.

3.2 Benefits of Using Database Configuration Assistant

Oracle recommends that you use DBCA to create your Oracle RAC database, because the preconfigured databases created by DBCA optimize your environment for features such as password security, the server parameter file (SPFILE), and automatic undo management. If you use Oracle ASM or cluster file system storage, then DBCA also configures automated backup, which uses the Fast Recovery Area.

DBCA enables you to create both policy-managed and administrator-managed databases. At the end of database creation, DBCA starts any database instances required to support your defined configuration.

With DBCA, you can create site-specific tablespaces as part of database creation. If you have data file requirements that differ from those offered by DBCA templates, then create your database with DBCA and modify the data files later. You can also run user-specified scripts as part of your database creation process.

3.3 Automatic Listener Migration from Earlier Releases

If your system has an Oracle Database 10g or 11g installation, and you install Oracle Database 11g release 2 (11.2) either to coexist with or to upgrade the Oracle Database 10.1, 10.2, or 11.1 installation, then most installation types automatically migrate the existing Oracle Database listener to the 11g release 2 (11.2) Oracle home. During migration, they configure and start a default Oracle Net listener using the same TCP/IP port as the existing listener, with the IPC key value.

During the Oracle Clusterware upgrade to 11g release 2 (11.2) the default listener (LISTENER_NODENAME was migrated to the Oracle grid infrastructure home (Grid home). DBCA always uses the default listener.

The listener migration process stops the listener in the existing Oracle home, and restarts it in the new Oracle home. If the database was using the default listener (LISTENER_NODENAME), then it was migrated automatically to the Oracle Clusterware home by NETCA as part of the Oracle Clusterware upgrade. If the database was using a nondefault listener, then DBUA migrates the nondefault listener to the Oracle Database home.

During migration, client applications may not be able to connect to any databases that are registered to the listener that is being migrated.

3.4 Verifying Requirements for DBCA

If you want to use DBCA to change database configuration, then use Cluster Verification Utility (CVU) to verify that your system is prepared for configuration changes using the following command syntax:

Grid_home\bin\cluvfy stage -pre dbcfg -n node_list -d Oracle_home [-verbose]

In the preceding syntax example, the variable Grid_home is the Oracle grid infrastructure home, the variable node_list is the list of nodes in your cluster, separated by commas, and the variable Oracle_home is the path for the Oracle home directory where OUI creates or modifies the database.

For example, to perform a check to determine if your system is prepared for an Oracle Database with Oracle RAC installation on a two-node cluster with nodes node1 and node2, with the Oracle grid infrastructure home pathC:\app\grid, and with the Oracle home path C:\app\oracle\product\11.2.0\dbhome1, then enter the following command:

C:\app\grid\bin> cluvfy stage -pre dbcfg -n node1,node2 \
-d C:\app\oracle\product\11.2.0\dbhome1

You can select the option -verbose to receive progress updates as the CVU performs its system checks, and detailed reporting of the test results.

If the CVU summary indicates that the cluster verification check fails, then review and correct the relevant system configuration steps, and run the test again.

The command cluvfy stage -pre dbcfg verifies the following:

Node Reachability: All the specified nodes are reachable from the local node.
User Equivalence: User equivalence exists on all the specified nodes.
Node Connectivity: Connectivity exists between all the specified nodes through the available public and private network interfaces.
Administrative Privileges: The installation user (typically oracle) has proper administrative privileges on the specified nodes for creating an Oracle RAC database.
Oracle Clusterware Integrity: All the components of the Oracle Clusterware stack are fully operational.

3.5 Creating an Oracle RAC Database with DBCA

To create an Oracle RAC database with DBCA without Oracle ASM or a cluster file system, you must have configured shared storage devices. In addition, you must have run the Oracle Net Configuration Assistant (NETCA) to configure your Oracle Net listener.ora file.

On Windows-based systems, if you plan to use Oracle ASM storage, then before you use DBCA to create a database, you must first create logical partitions without primary partitions on the same drive and delete the drive letters for these partitions on all nodes, or stamp these partitions with asmtool. Refer to the Oracle Grid Infrastructure Installation Guide for Microsoft Windows for more information on configuring disk devices for use with Oracle ASM.

To s tart DBCA, connect as the installation owner account (for example, oracle)to one of your nodes where Oracle RAC is installed, and enter the command dbca command from the Oracle_home\bin directory. On Windows-based platforms, you can also click Start, and select Programs, Oracle - Oracle_home name, Configuration and Migration Tools, and then Database Configuration Assistant.

When you start DBCA, the first page it displays is the Welcome page for Oracle RAC, which includes the option to select an Oracle RAC database. DBCA displays this Oracle RAC Welcome page only if the Oracle home from which it is started was installed on a cluster. Enter information as prompted by DBCA. Click Help if you need assistance.

If DBCA does not display the Welcome page for Oracle RAC, then DBCA was unable to detect if the Oracle home is installed on a cluster. In this case, check that the OUI inventory is correctly located in the directory C:\Program Files\Oracle\Inventory\oraInst.loc, and that the inventory files are not corrupted. Also, perform clusterware diagnostics by using the following CVU command syntax:

cluvfy stage -post crsinst -n nodelist.

For example, on a cluster with nodes node1 and node2, run the following command:

C:\app\grid\bin\cluvfy stage -post crsinst -n node1,node2

Note the following important information when using DBCA:

If nodes that are part of your cluster installation do not appear on the Node Selection page, then execute the opatch -lsinventory command to perform inventory diagnostics and CVU to perform clusterware diagnostics.
The global database name is of the form database_name.domain. The global database name can be up to 30 characters in length, and must begin with an alphabetic character. The domain portion of the global database name can be no more than 128 characters and can contain only alphabetic and numeric characters, as well as the period (.) character.
A system identifier (SID) is used as an identifier unique to each Oracle instance. The system identifier (SID) prefix, or first 8 characters, must begin with an alphabetic character. For Oracle RAC database, the SID prefix is limited to 8 characters, and only letters and numeric digits are permitted. On some platforms, the SID is case-sensitive.

Note:
It is common practice to set the SID to be equal to the database name. The maximum number of characters for the database name is 8. For more information, see the discussion of the DB_NAME initialization parameter in Oracle Database Reference.
On the Management Options page, you are provided with selections for Oracle Enterprise Manager monitoring and management interfaces.

Database Control is always an option. If DBCA discovers Grid Control agents on the cluster, then it also provides you with the option Enterprise Manager with the Grid Control. Choose between Database Control and Grid Control interfaces.

You can set up e-mail notification and enable daily backup operations. For e-mail notifications, you provide the outgoing mail server and e-mail address. For daily backups, you enter the backup time and operating system credentials for the user that performs backup operations.
To use a fast recovery area, Oracle recommends that you create at least two separate Oracle ASM disk groups: one for the database data files and one for the fast recovery area. Oracle recommends that you place the database data files and the fast recovery area in separate failure groups using shared storage.

A failure group is defined by shared hardware, such as a controller shared between two storage devices, or two disks that are on the same spindle. If two storage devices share hardware that could fail, making both storage devices unavailable, then these storage devices are said to be in the same failure group.

If you do not use Oracle ASM, then Oracle recommends that you store the data files and the fast recovery area on shared storage outside of the Oracle home and in separate locations, similar to using separate Oracle ASM failure groups, so that a hardware failure does not affect availability.
See Also:
- Oracle Database Concepts for more information about using a fast recovery area
- Oracle Database Storage Administrator's Guide for information about failure groups and best practices for high availability and recovery
On the Oracle ASM Disk Groups page, if you do not see the storage devices that you want to add, then click Change Disk Discovery Path to alter the search path used by DBCA to find available storage devices, or click Stamp Disks to start the asmtoolg GUI tool. You can select storage devices with a status of Candidate or Former (never used in an Oracle ASM disk group or no longer in a group). If you want to add storage devices that still have Oracle ASM disk headers, but the disk group is no longer in use (a case that can occur if you are selecting storage devices after an aborted installation attempt, you attempted deinstallation without dropping the disk group, or other configuration problems), then use the Force command.

See Also:
Oracle Database Installation Guide for Microsoft Windows for more information about asmtoolg
On the Recovery Configuration page, if you are using Oracle ASM or cluster file system storage, then you can also select the fast recovery area and size on the Recovery Configuration page. If you are using Oracle ASM, then the fast recovery area defaults to an Oracle ASM disk group. If you are using Oracle CFS, then the fast recovery area defaults to Oracle_home\fast_recovery_area.
For all platforms, if you intend to add more nodes in your cluster than you have during the current DBCA session, then click All Initialization Parameters, and change the parameter CLUSTER_DATABASE_INSTANCES to the total number of nodes that you plan to add to the cluster.

In addition, if you click All Initialization Parameters, note that if your global database name is longer than 8 characters, then the database name value (in the DB_NAME parameter) is truncated to the first 8 characters, and the DB_UNIQUE_NAME parameter value is set to the global name.

See Also:
Oracle Database Administrator's Guide for information about initialization parameters

After you respond to DBCA prompts, review the Summary dialog information and then click OK. DBCA does the following:

Starts the Oracle services if you are on a Windows-based platform
Configures the network for the cluster database
Migrates previous release Oracle Database listeners and related files to the Oracle Database 11g Oracle home
Creates an Oracle RAC database and its instances
Creates the Oracle RAC data dictionary views
Configures Oracle Enterprise Manager Database Control or Grid Control
Starts the listeners and database instances, and then starts the high availability services

Caution:

After you have created the database, if you decide that you want to install additional Oracle Database products in the database you have created, then you must stop all processes running in the Oracle home before you attempt to install the additional products. Refer to Appendix E, "How to Stop Processes in an Existing Oracle Real Application Clusters Database" for additional information.

3.6 Deleting an Oracle RAC Database with DBCA

This section explains how to delete an Oracle RAC database with DBCA. This process deletes a database and removes a database's initialization parameter files, instances, OFA structure, and Oracle network configuration. However, this process does not remove data files if you placed the files on raw devices or on raw partitions.

To delete a database with DBCA:

Start DBCA on one of the nodes:.

On Windows-based platforms, click Start, and select Programs, Oracle - Oracle_home name. In the Configuration and Migration Tools folder select Database Configuration Assistant

The DBCA Welcome page appears.
Select Oracle Real Application Clusters database, then click Next.

After you click Next, DBCA displays the Operations page.
Select Delete a database, and then click Next.

DBCA displays the List of Cluster Databases page.
If your user ID and password are not operating-system authenticated, then the List of Cluster Databases page displays the user name and password fields. If these fields appear, then enter a user ID and password for a user account that has SYSDBA privileges.
Select the database to delete, and click Finish.

After you click Finish, DBCA displays a dialog box to confirm the database and instances that DBCA is going to delete.
Click OK to begin the deletion of the database and its associated files, services, and environment settings, or click Cancel to stop the operation.

If you clicked OK, then DBCA continues the operation and deletes all the associated instances for this database. DBCA also removes the parameter files and password files.

At this point, you have accomplished the following:

Deleted the selected database from the cluster
Deleted the Oracle services for the database on Windows-based platforms
Deleted high availability services that were assigned to the database
Deleted the Oracle Net configuration for the database
Deconfigured Database Control for that database
Deleted the OFA directory structure for that database from the cluster
Deleted the data files if the data files were not on raw devices

3.7 Configuring Database Control During Installation

If you create a database while installing Oracle RAC 11g release 2 (11.2), then you have the option of configuring your database so it can be managed by Oracle Enterprise Manager Grid Control Console, or by Oracle Enterprise Manager 11g Database Control Console.

When you configure Database Control for your Oracle RAC database, for each Oracle RAC instance on a node, the following subdirectory is created, where Oracle_home is the directory where the Oracle RAC software is installed, nodename is the name of the node in the cluster and DBUniqueName is the database unique name:

Oracle_home\nodename_DBUniqueName

To select Grid Control Console as your management option, the Oracle Management Service must be installed on a network host. In addition, the Oracle Management Agent must be installed on the host where you are installing the database. Otherwise, the Grid Control Console option is unavailable, and you must instead choose to manage your database with Database Control.

For most Oracle RAC 11g release 2 (11.2) installation types, you must choose either Database Control or Grid Control as your management option when you create a database during the installation. However, if you create a database using one of the following methods, then you can choose not to configure Database Control:

Choosing the Advanced database configuration option during an Enterprise or Standard Edition installation
Running Database Configuration Assistant (DBCA) after the installation

If you do not configure Database Control during the Oracle RAC 11g release 2 (11.2) installation, then no hostname_dbuniquename directory is created in the resulting Oracle home directory.