6
Configuring the Server Parameter File in Real Application Clusters Environments

This chapter describes server parameter file placement and configuration in Real Application Clusters environments. The topics in this chapter are:

• Parameter Files and Real Application Clusters

• Using The Server Parameter File in Real Application Clusters

• Parameter File Search Order

• Migrating to the Server Parameter File in Real Application Clusters Environments

• Server Parameter File Errors

• Backing Up the Server Parameter File

  See Also: Oracle9i Real Application Clusters Administration for more information about parameters in Real Application Clusters environments and Oracle9i Real Application Clusters Deployment and Performance for a discussion of parallel execution-related parameters in Real Application Clusters data warehouse environments

Parameter Files and Real Application Clusters

Oracle uses parameter settings in parameter files to determine how to control various database resources. You can use two types of files for parameter administration: the server parameter file or one or more traditional client-side parameter files.

Oracle Corporation recommends that you administer parameters using the server parameter file. If you use the traditional client-side parameter files, parameter changes that Oracle makes for self-tuning are not preserved after shutdown.

See Also: Oracle9i Real Application Clusters Administration for more information on using client-side parameter files in Real Application Clusters

Using The Server Parameter File in Real Application Clusters

By default, Oracle creates the server parameter file based on one SPFILE. You can only change parameter settings in the server parameter file using Oracle Enterprise Manager or ALTER SYSTEM SET SQL statements; the server parameter file is a binary file that you cannot directly edit.

Note: Oracle Corporation recommends that you avoid modifying the values for self-tuning parameters; overriding these settings can adversely affect performance.

If you are migrating from a previous Oracle release, create and configure the server parameter file for Real Application Clusters using the procedures described in the following section.

Location of The Server Parameter File

The default location of the server parameter file when the database creates it from PFILEs is platform-dependent.

The default location of the server parameter file on UNIX is:

$ORACLE_HOME/dbs/spfile$ORACLE_sid.ora 

The default location of the server parameter file on Windows NT and Windows 2000 is:

%ORACLE_HOME%\database\SPFILE%ORACLE_SID%.ORA 

The default location of the server parameter file is inappropriate for Real Application Clusters databases because all instances must use the same server parameter file.

Instead, for UNIX platforms Oracle Corporation recommends that you use a PFILE in:

$ORACLE_HOME/dbs/initsid.ora

For Windows NT and Windows 2000 platforms Oracle Corporation recommends that you use a PFILE in:

%ORACLE_HOME%\database\initsid.ora

This file is for each instance and it references a single, shared initialization parameter file. The file must contain the following entry for UNIX platforms:

SPFILE='/dev/vx/rdsk/oracle_dg/db_spfile'

The file must contain the following entry for Windows NT and Windows 2000 platforms:

SPFILE='db_spfile1'

However, if your platform supports a cluster file system, use an alternate file location of:

SPFILE= $ORACLE_HOME/dbs/spfile.ora

You must use the same value of SPFILE so that all instances use the same server parameter file at startup.

To use the DBCA to create your database and to use the server parameter file, on the Initialization Parameters page select the Create server parameter file (spfile) box under the File Locations tab. Then enter the raw device path name in the Persistent Parameters Filename field as shown in Figure 6-1.

Figure 6-1 File Locations Tab For Initialization Parameters

Text description of the illustration fileloc2.gif

Note: When you use the DBCA to create the server parameter file, the PFILE file name is $ORACLE_HOME/dbs/initsid.ora on UNIX and %ORACLE_HOME%\database\initsid.ora on Windows NT and Windows 2000. These are the default PFILE names.

Parameter File Search Order

Oracle searches for your initialization parameter file in a particular order depending on your platform. On UNIX platforms, Oracle examines directories in the following order:

1. $ORACLE_HOME/dbs/spfilesid.ora

2. $ORACLE_HOME/dbs/spfile.ora

3. $ORACLE_HOME/dbs/initsid.ora

The search order on Windows NT and Windows 2000 platforms is:

1. %ORACLE_HOME%\database\spfilesid.ora

2. %ORACLE_HOME%\database\spfile.ora

3. %ORACLE_HOME%\database\initsid.ora

Migrating to the Server Parameter File in Real Application Clusters Environments

To migrate to the server parameter file, create and edit the server parameter file using the procedures described in this section.

Server Parameter File Placement in Real Application Clusters

Put the server parameter file on a raw device that is at least 5MB in size. For single-node cluster-enabled configurations, or if you are using a cluster file system, place the server parameter file on a file system.

Procedures for Migrating to the Server Parameter File

Migrate to the server parameter file by completing the following procedures:

Note: The following procedures show examples for UNIX only.

1. Combine the initialization parameter files for all instances into a single initdbname.ora file by copying all shared IFILE contents as is. All parameters defined in your IFILE parameter files are global. Therefore, create them as "parameter=value" without sid prefixes.

2. Copy all instance-specific parameter definitions from INITsid.ORA files using the following syntax where sid is the sid of the instance:

   sid.parameter=value 
   
   

3. Create the server parameter file using the CREATE SPFILE statement. For example:

   CREATE SPFILE='/dev/vx/rdsk/oracle_dg/db_spfile' 
   FROM PFILE='?/dbs/initdb_name.ora'
   
   

This statement reads your combined initdbname.ora file that you created by merging your IFILEs. Then it transfers the settings for the parameters from the merged file into your server parameter file.

4. Oracle Corporation recommends that you use the server parameter file by executing the STARTUP command as in this example:

   STARTUP PFILE=$ORACLE_HOME/dbs/initsid.ora
   
   

Where the file initsid.ora contains the entry:

SPFILE='/dev/vx/rdsk/oracle_dg/db_spfile'

If you use this STARTUP command syntax, Oracle uses the server parameter file entry specified in initsid.ora.

Note: The release 8.1 default of using a client-side PFILE to startup a database instance is no longer supported.

Server Parameter File Errors

Oracle reports errors that occur during the server parameter file creation or while reading the file during startup. If an error occurs during a parameter update, Oracle records the error in your ALERT.LOG file and ignores subsequent parameter updates to the file. If this happens, you can do any of the following:

• Shutdown the instance, recover the server parameter file, and restart the instance.

• Allow the instance to continue running without regard for subsequent parameter updates.

Oracle displays errors for parameter changes that you attempt when you incorrectly use the ALTER SYSTEM SET statement. Oracle does this when an error occurs while reading from or writing to the server parameter file.

Backing Up the Server Parameter File

Oracle Corporation recommends that you regularly create copies of the server parameter file for recovery purposes. Do this using the CREATE PFILE statement. For example:

CREATE PFILE='?/dbs/initdb_name.ora'
FROM SPFILE='/dev/vx/rdsk/oracle_dg/db_spfile'

You can also recover by starting up an instance using a client-side initialization parameter file. Then re-create the server parameter file using the CREATE SPFILE statement. You cannot use RMAN (Recovery Manager) to create backups of the server parameter file.

See Also: Oracle9i SQL Reference for more information about the CREATE SPFILE statement