Creating a 10g Database on OCFS

Oracle Database Tips by Donald Burleson

The following walks through the steps for creating a 10g RAC database.

1. Use oraenvor racenvto set the environmental variables and launch the dbca. Use the ampersand to launch the configuration assistant as a background process, freeing up the prompt for use.

2. Choose to create or configure a Real Application Cluster database.

3. Choose to Create a Database.

4. Ensure that all nodes are selected.

5. Select Custom Database.

6. Use any name you wish except that of a pre-existing database.

7. If you choose to configure a database with Enterprise Manager, be aware that doing so will launch the emwd.ps daemon. This will allow you to manage the database from a browser on a remote computer. Take note of the URL displayed on the ?Database creation complete? screen at the end of the install.

8. It is easier to use the same password for all accounts.

9. This new feature is a big improvement over the 9i version of dbca. Choose Cluster File System and continue.

10. Indicate a directory on shared storage as shown.

11. This book does not cover Flash Recovery or Archiving so deselect these. Visit this book's support website for details on these features. (http://www.database-expert.com/rac).

12. To save time on database creation, eliminate all unnecessary options as shown. If you chose to configure the database with Enterprise Manager, then leave the checkbox for the EM repository checked.

13. Configure the database service and TAF policy as shown. A database service adds entries to the tnsnames.ora file and resources to the CRS. This allows connections to failover to a backup instance in the event of instance failure. See Appendix H for more information about database services for high availability.

14. This is simply a warning; do not configure memory usage below 44%.

15. Depending on the available RAM, 60% memory allocation is a good start.

16. Verify the file locations for the datafiles.

17. Choose to Create Database.

18. Review the parameters before the last OK button is clicked.

19. If the options were not included, database creation will take about an hour. If an error occurs, it will almost certainly happen in the first minute or two.

20. If the Enterprise Manager was chosen, write down the URL shown on this screen. Once the OK button is clicked on this screen, allow several minutes for the database to be started on each node. The following message will pop up and eventually disappear.

The Oracle 10g RAC database configuration is far different from the 9i database configuration. By default, CRS will attempt to keep everything, including databases, running at all times. If nodes are rebooted at this time, the instances will be restarted automatically.

Check the status of services with the crs_status command as shown in Figure 9.2. 10g databases will be listed in the output of this command. However 9i databases, even when registered in the CRS, will not.

What are these additional resources in the CRS that end with ?.cs? and ?.srv?? These are the resources for the database high availability service that were created. The following commands can be used to read each service's complete configuration, including Oracle's description.

$ORA_CRS_HOME/bin/crs_stat ?p ora.fast.fast_conn.cs
$ORA_CRS_HOME/bin/crs_stat ?p ora.fast.fast_conn.fast1.srv
$ORA_CRS_HOME/bin/crs_stat ?p ora.fast.fast_conn.fast2.srv

Turn to Appendix H for more information about configuring database services for high availability.

10g srvctl

With the new Cluster Ready Services added to Oracle 10g software, a number of new commands are available. For example, the srvctl utility is now used to start, stop and check the status of vip, gsd, listener, and ons as a group. This group of programs is referred to as ?nodeapps.? Figure 9.3 demonstrates checking the status of nodeapps.

A few new verbs have been added to srvctl's vocabulary. The following table provides some examples:

### Disable a database so that it does not start on boot:
srvctl stop database ?d mydb
srvctl disable database ?d mydb

### Enable a database:
srvctl enable database ?d mydb

### Make an instance dependent on another service
### (mydb will not be started until +ASM service is running)
srvctl modify instance ?d mydb ?i mydb1 's +ASM1
srvctl modify instance ?d mydb ?i mydb2 's +ASM2

For a more complete list of new srvctl functionalities, visit the website http://tahiti.oracle.com to find the Oracle Real Application Clusters Administrator's Guide (Part Number B10765-02), and look for the subheading ?B Server Control (SRVCTL) Reference.?

CRS Utilities

A number of CRS utilities, as listed in Figure 9.4, are included with 10g Cluster Ready Services. Looking at the help available for each of these programs through the command and the tag ?help, demonstrates that most of these programs can do many things.

Unfortunately, these programs are poorly documented by Oracle. What you should know about them is that they can be used to add 3^rd party applications to a cluster for fault tolerance.

Figure 9.5 demonstrates using the crs_startscript to start a database service after it has been shutdown by srvctl. Even though the response from the program only mentions member ?oracle1?, the database is started on both nodes. This is only shown as a demonstration; I suggest using srvctl to start and stop databases.

Before building the next database, it is a good idea to shutdown the existing database and to prevent it from restarting. Use srvctl to disable the database with the following commands:

srvctl stop database ?d fast
srvctl disable database ?d fast

Figure 9.6 demonstrates shutting down the existing database with srvctl and removing its services from the CRS repository. Note that when attempting to remove the last instance, the error PRKP-1075 is returned. All instances are removed when the database is removed, which means that removing the instances prior to removing the database is unnecessary.

From experience, I have found it is better to use srvctl to remove a database configuration than it is to use the $ORA_CRS_HOME/bin/crs_unregistercommand. The latter command leaves too much of the configuration orphaned in the CRS file, making it impossible to add a database with the same name back in later. However, crs_unregister can be used to clean up any orphan configuration that srvctl missed. An example can be found in Appendix C.

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