3 Creating Oracle RAC Databases with the Database Configuration Assistant

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

• 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.

In addition DBCA has the following primary ASM functions:

• Configure and delete Automatic Storage Management (ASM)

• Provide an ASM instance for an Oracle Database node that is added to an existing Oracle RAC database that uses ASM, if ASM is not already configured on the node that is added to the Oracle RAC database

• Automatically extend an ASM instance on any node where you attempt to perform any ASM configuration operations (such as mount) on a node where ASM is not already configured

3.2 Benefits of Using Database Configuration Assistant

Oracle recommends that you use DBCA to create your Oracle RAC database, because DBCA's preconfigured databases optimize your environment for features such as ASM, the server parameter file, and automatic undo management. DBCA also provides pages to create new ASM disk groups if they are needed; if you use ASM or cluster file system storage, then DBCA also configures recovery and backup disk space.

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

DBCA also configures your Oracle RAC environment for various Oracle high availability features, such as services and cluster administration tools. It also starts any database instances required to support your defined configuration.

3.3 Verifying DBCA Requirements

To help to verify that your system is prepared to create the oracle database with Oracle RAC successfully, enter a cluster verification utility command using the following command syntax:

cluvfy.bat stage -pre dbcfg -n node_list -d oracle_home [-verbose]

In the preceding syntax example, 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 under which the database is to be created or its configuration is to be modified.

For example, to perform a check to determine if your system is prepared for an Oracle database with Oracle RAC on a two-node cluster with nodes node1 and node2, and with the Oracle home path c:\oracle\product\11.1.0, enter the following command:

cluvfy.bat stage -pre dbcfg -n node1,node2 -d c:\oracle\product\11.1.0

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 failed, 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: the connectivity exists between all the specified nodes through the available public and private network interfaces

• Administrative privileges: the current user 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 operational

3.4 Creating an Oracle RAC Database with DBCA

On Windows-based platforms, click Start, and select Programs, Oracle - Oracle_home name, Configuration and Migration Tools, and then Database Configuration Assistant

To create a database with DBCA in standalone mode without 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 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.

If you select DBCA templates that use preconfigured data files and if you do not use ASM or a cluster file system, then during database creation, DBCA first verifies that you created shared storage devices for each tablespace. If you have not configured the shared storage devices, then you must configure the devices and replace the default data file names that DBCA provides with the device names on the DBCA Storage page to continue database creation.

To start DBCA, connect as the Administrator to one of your nodes where Oracle RAC is installed and enter the command dbca command from the %ORACLE_HOME%\bin directory.

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.

If the Oracle RAC Welcome page opens, then provide 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. Perform clusterware diagnostics by using the following CVU command syntax:

CRS_home\bin\cluvfy\runcluvfy.bat stage -post crsinst -n nodelist.

For example, if the Oracle Clusterware software is installed in D:\crs and the cluster consists of nodes node1 and node2, run the following command:

D:\crs\bin\cluvfy.bat 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 run the opatch -lsinventory command to perform inventory diagnostics and clusterware diagnostics.

• The Global Database Name is of the form database_name.domain. The global database name can contain no more than 30 characters (alphanumeric, underscore (_), dollar ($), and pound (#)), and must begin with an alphabetic character. The domain portion of the global database name can contain no more than 128 characters (alphanumeric, underscore (_), and pound (#)), inclusive of all periods.

• The SID prefix must begin with an alphabetic character.

• The SID can have no more than 64 characters (alphanumeric, dollar ($), and pound (#)). DBCA uses the SID prefix to generate a unique value for the variable ORACLE_SID for each instance.

• 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 flash recovery area, Oracle recommends that you create at least two separate ASM disk groups: one for the database area and one for the recovery area. Oracle recommends that you place the database area and the recovery area in separate failure groups.

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

  If you do not use ASM, then Oracle recommends that the data files and the Flash Recovery area are located outside of the Oracle home, in separate locations, as with separate ASM failure groups, so that a hardware failure does not affect availability.

  See Also:

  Oracle Database Concepts for more information about using a flash recovery area, and Oracle Database Storage Administrator's Guide for information about failure groups and best practices for high availability and recovery

• If you do not see the disks that you want to add, then click Change Disk Discovery Path to alter the search path used by DBCA to find available disks, or click Stamp Disks to start the asmtoolg GUI tool. (refer to Database IG for details).

  See Also:

  Oracle Database Installation Guide for Microsoft Windows for more information about asmtoolg

• If DBCA displays the following message:

  The file oracle_home\bin\oracle does not exist on node node_name. 
  Make sure that file exists on these nodes before proceeding.
  

  This message means that the Oracle home from which the first ASM instance in the cluster runs is not installed on these cluster nodes. You must extend the ASM Oracle home to these nodes by performing the procedure documented in "Step 4: Adding Nodes at the Oracle RAC Database Layer" in the Oracle Real Application Clusters Administration and Deployment Guide. However, do not perform Step 5 in that section. OUI extends the ASM Oracle home to the selected nodes and performs any configuration required for running an ASM instance on these nodes.

• If DBCA displays the following message:

  Please run the DBCA from one of the nodes that has an existing ASM instance node_list.
  

  This message means that you are attempting to create an Oracle RAC database using ASM storage, but the ASM instance does not exist on the node from which you ran DBCA. However, ASM instances do exist on the remote nodes that appear in the message node list. In this case, DBCA cannot clone the existing ASM instance from the remote node to the local node. To correct this, start DBCA from one of the nodes shown in the node list to create your Oracle RAC database using ASM storage. This copies the local node's ASM instance and modifies its parameters and attributes to create ASM instances on the nodes in your cluster that do not have ASM instances.

• On the Recovery Configuration page, if you are using ASM or cluster file system storage, then you can also select the flash recovery area and size on the Recovery Configuration page. If you are using ASM, then the flash recovery area defaults to the ASM Disk Group. If you are using OCFS, then the flash recovery area defaults to %ORACLE_BASE%\flash_recovery_area.

• 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 number of nodes that you will 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 Reference for information about initialization parameters

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

• Creates an operative Oracle RAC database and its instances

• Creates the Oracle RAC data dictionary views

• Configures the network for the cluster database

• Starts the Oracle services if you are on a Windows-based platform

• Migrates previous release Oracle Database listeners and related files to the Oracle Database 11g Oracle home

• Starts the listeners and database instances, and then starts the high availability services

• Configures Oracle Enterprise Manager Database Control or Grid Control

3.5 Automatic Listener Migration from Earlier Releases

If your system has an Oracle Database 10g (10. 1) installation, and you install Oracle Database 11g release 1 (11.1) either to coexist with or to upgrade the Oracle Database 10.1 or 10.2 installation, then most installation types automatically migrate the Oracle Database 10.1 listener to the 11g release 1 (11.1) 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 EXTPROC. This process occurs through one of the following scenarios:

• During a coexisting installation, DBCA automatically migrates the listener and related files from the Oracle Database 10.1 or 10.2 Oracle home to the Oracle Database 11g Oracle home.

• During an upgrade, Oracle Database Upgrade Assistant (DBUA) automatically locates the Oracle 10g release 1 (10.1) or release 2 (10.2) listener, and migrates it to Oracle 11g release 1 (11.1).

The listener migration process stops the listener in the existing Oracle home, and restarts the listener from the new Oracle home. During migration, client applications may not be able to connect to any databases that are registered to the listener that is being migrated.

3.6 Deleting an Oracle Real Application Clusters 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 datafiles if you placed the files on raw devices or on raw partitions.

To delete a database with DBCA:

1. Start DBCA on one of the nodes:

   On Windows-based platforms, click Start, and select Programs, Oracle - Oracle_home name, Configuration and Migration Tools, then Database Configuration Assistant

   The DBCA Welcome page appears.

2. Select Oracle Real Application Clusters and click Next.

   After you click Next, DBCA displays the Operations page.

3. Select Delete a database, click Next. DBCA displays the List of Cluster Databases page.

4. 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 that has SYSDBA privileges.

5. Select the database to delete and click Finish.

   After you click Finish, DBCA displays a dialog to confirm the database and instances that DBCA is going to delete.

6. Click OK to begin the deletion of the database and its associated files, services, and environment settings, or click Cancel to stop the operation.

When you click OK, DBCA continues the operation and deletes all of 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 selected database's Oracle services for Windows-based platforms

• Deleted high availability services that were assigned to the database

• Deleted the Oracle Net configuration for the database

• Deleted the OFA directory structure from the cluster

• Deleted the datafiles if the datafiles were not on raw devices