6 Creating Oracle Real Application Clusters Databases with Database Configuration Assistant

6.1 Using Database Configuration Assistant in Oracle Real Application Clusters

DBCA has the following primary functions:

• Create the database and its instances

• Set up network configuration for database, instances and database services

• Register the database in Oracle Enterprise Manager Grid Control or configure Database Control

• Configure Automatic Storage Management (ASM)

• Start up the database, its instances, services, and any other node applications

  See Also:

  • "Creating an Oracle Real Application Clusters Database with DBCA" for more information about using DBCA in standalone mode

  • Oracle Database Net Services Administrator's Guide to resolve problems—for example, with the listener configuration—and for further information about Lightweight Directory Access Protocol (LDAP)-compliant directory support

6.2 Benefits of Using Database Configuration Assistant

Oracle recommends that you use Database Configuration Assistant (DBCA) to create your RAC database, because preconfigured databases optimize your environment for features such as Automatic Storage Management (ASM), the server parameter file (SPFILE), 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 automated backup, which uses the flash recovery area.

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.

DBCA also configures your 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.

6.3 Oracle Real Application Clusters High Availability Services

When you configure high availability services with the DBCA Database Services page, you can also configure service instance preferences and Transparent Application Failover (TAF) policies.

6.4 Automatic Listener Migration from Release 10.1 to 10.2

If your system has an Oracle Database Release 10g Release 10. 1 installation, and you install an Oracle Database 10g Release 2 (10.2) either to coexist with or to upgrade the Oracle Database 10.1 installation, then most installation types automatically migrate the Oracle Database 10.1 listener to the 10g Release 2 (10.2) 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 EXTPROC. This process occurs through one of the following scenarios:

• During a coexisting installation, Database Configuration Assistant (DBCA) automatically migrates the listener and related files from the 10.1 Oracle home to the 10.2 Oracle home.

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

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.

6.5 Verifying Requirements for DBCA

To help to verify that your system is prepared to create Oracle Database with RAC successfully, enter a Cluster Verification Utility (CVU) command using the following command syntax:

/mountpoint/crs/Disk1/cluvfy/runcluvfy.sh stage -pre dbcfg -n node_list -d oracle_home [-verbose]

In the preceding syntax example, the variable mountpoint is the mountpoint of the installation media, 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 RAC on a two-node cluster with nodes node1 and node2, with the mountpoint /dev/dvdrom/, and with the Oracle home path /oracle/product/10.2.0, enter the following command:

/dev/dvdrom/crs/Disk1/cluvfy/runcluvfy.sh stage -pre dbcfg -n node1,node2 -d /oracle/product/10.2.0/

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 fails, then review and correct the relevant system configuration steps, and run the test again.

The command runcluvfy.sh 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 oracle user has proper administrative privileges on the specified nodes for creating a RAC database.

• Oracle Clusterware Integrity: All the components of the Oracle Clusterware stack are fully operational.

6.6 Creating an Oracle Real Application Clusters Database with DBCA

To create a database with DBCA in standalone mode without ASM or a cluster file system, you must have configured each raw device as described in Appendix C. In addition, you must have run the Oracle Net Configuration Assistant (NETCA) to configure your Oracle Net listener.ora file.

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 the raw devices for each tablespace. If you have not configured the raw devices, then you must configure the raw devices and replace the default data file names that DBCA provides with raw device names on the DBCA Storage page to continue database creation.

To start DBCA, connect as the oracle user to one of your nodes where 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 Real Application Clusters (RAC) database. DBCA displays this RAC-specific Welcome page only if the Oracle home from which it is started was cluster-installed.

If DBCA does not display the Welcome page for Oracle RAC, then DBCA was unable to detect if the Oracle home is cluster-installed. In this case, check that the OUI inventory is correctly located in the directory /etc/oraInst.loc, and that the oraInventory file is not corrupted. Also, perform clusterware diagnostics by running the CVU command /mountpoint/crs/Disk1/cluvfy/runcluvfy.sh stage -post crsinst -n nodename.

If the RAC Welcome page opens, then provide information as prompted by DBCA. Click Help if you need assistance.

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 olsnodes command to perform inventory diagnostics and clusterware diagnostics.

• The global database name can be up to 30 characters in length, and must begin with an alphabetic character. The SID prefix must begin with an alphabetic character.

• The maximum number of characters you can use for the SID prefix is 8 characters. DBCA uses the SID prefix to generate a unique value for the variable ORACLE_SID for each instance.

• On the Management Options page, if you select the option Enterprise Manager with the Grid Control, and DBCA discovers agents. If you select the option Database Control, then 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 two separate ASM disk groups: one for the database area and one for the recovery area.

  See Also:

  Oracle Database Concepts for more information about using a flash recovery area

• On the ASM Disk Groups page, 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. You can select disks with a status of Candidate or Former (never used in an ASM disk group or no longer in a group) by selecting the check box. If you want to add disks that still have ASM disk headers, but the disk group is no longer in use (a case that can occur if you are selecting disks after an aborted install, a de-install performed without dropping the disk group, or other configuration problems), then use the Force command.

• 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 Database Oracle Clusterware and 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 a 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 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.

• On the Initialization Parameters page, set the value of the CLUSTER_DATABASE_INSTANCES parameter to the number of instances you intend to use in the cluster if you are not including all the related nodes during the current execution of DBCA.

  In addition, 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.

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

• Creates an operative RAC database and its instances

• Creates the RAC data dictionary views

• Configures the network for the cluster database

• Migrates Oracle Database 10g Release 1 (10.1) listener and related files to the 10.2 Oracle home

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

• Configures Enterprise Manager Database Control or Grid Control

6.7 Deleting an Oracle Real Application Clusters Database with DBCA

This section explains how to delete a RAC database with DBCA. This process deletes a database and removes a database's initialization parameter files, instances, OFA structure, and an 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:

1. Start DBCA on one of the nodes.

   • Run the DBCA command from the $ORACLE_HOME/bin directory.

   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, and 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 box 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 the associated instances for this database. DBCA also removes the parameter files, password files, and oratab entries.

At this point, you have accomplished the following:

• Deleted the selected database from the cluster

• Deleted high availability services that were assigned to the database

• Deleted the Oracle Net configuration for the database

• Deconfigures Database Control

• Deleted the OFA directory structure from the cluster

• Deleted the data files if the data files were not on raw devices