13 Configuring the Server Parameter File in Real Application Clusters Environments

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

Parameter Files and Real Application Clusters
Using Server Parameter Files in Real Application Clusters
Parameter File Search Order in Real Application Clusters
Migrating to the Server Parameter File in Real Application Clusters Environments

Server Parameter File Errors in Real Application Clusters

See Also:

The Oracle Real Application Clusters Administrator's Guide for more information about parameters and the Oracle Real Application Clusters Deployment and Performance Guide for a discussion of parallel execution-related parameters in RAC 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 (spfile) or one or more traditional client-side parameter files.

Oracle recommends that you administer parameters using spfile. If you use client-side parameter files, then Oracle does not preserve parameter changes made for self-tuning after shutdown.

See Also:

The Oracle Database 10g Real Application Clusters documentation for more information about using client-side parameter files

Using Server Parameter Files in Real Application Clusters

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

Note:

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

If you are upgrading from a previous Oracle release, then create and configure the server parameter file for RAC 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 a PFILE is platform-dependent.

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

$ORACLE_HOME/dbs/spfile$ORACLE_SID.ora

The default location of the server parameter file on Windows-based platforms is:

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

The default location of the server parameter file is inappropriate for RAC databases if you use raw devices because all instances must use the same server parameter file.

Instead, for UNIX-based systems Oracle recommends that you use a PFILE in this directory:

$ORACLE_HOME/dbs/init$ORACLE_SID.ora

For Windows-based platforms Oracle recommends that you use a PFILE in this directory:

%ORACLE_HOME%\database\init%ORACLE_SID%.ora

This path is valid for each instance and it refers to a single, shared initialization parameter file. If you use raw storage, then the file must contain the following entry on a UNIX-based system:

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

and the following entry on a Windows-based platform:

SPFILE='\\.\dbname_SPFILE'

However, if you use a cluster file system, then use one of the following alternate file locations:

On UNIX-based systems:
```
SPFILE='$ORACLE_HOME/dbs/spfile.ora'
```

On Windows-based systems:

SPFILE=%ORACLE_HOME%\database\spfile.ora

If you use ASM, then the SPFILE value will be:

SPFILE='+disk_group_name/dbunique_name/spfiledbname.ora'

where dbunique_name is the unique database name and dbname is the database name.

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 Create server parameter file (spfile) under the File Locations tab which is visible only if you are using raw storage. Then enter either a shared file system filename or the raw device path name in the Server Parameters Filename field.

Note:

When you use the DBCA to create the server parameter file, the default PFILE file name is $ORACLE_HOME/dbs/init$ORACLE_SID.ora on UNIX-based systems and %ORACLE_HOME%\database\init%ORACLE_SID%.ora on Windows-based platforms. These are the default PFILE names.

Parameter File Search Order in Real Application Clusters

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

$ORACLE_HOME/dbs/spfilesid.ora
$ORACLE_HOME/dbs/spfile.ora
$ORACLE_HOME/dbs/initsid.ora

The search order on Windows-based platforms is:

%ORACLE_HOME%\database\spfilesid.ora
%ORACLE_HOME%\database\spfile.ora
%ORACLE_HOME%\database\initsid.ora

Migrating to the Server Parameter File in Real Application Clusters Environments

Migrate to the server parameter file by creating and editing the server parameter file using the procedures described in this section.

Server Parameter File Placement in Real Application Clusters

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

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-based systems only.

Combine the initialization parameter files for all instances into one 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.
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 
```
If you are using a cluster file system, then create the server parameter file using the CREATE SPFILE statement as in the following example:
```
CREATE SPFILE='?/dbs/spfile_dbname.ora'
FROM PFILE='?/dbs/initdbname.ora'
```
If you use ASM, then use the following syntax to create the server parameter file:
```
CREATE SPFILE='/+disk_group_name/db_uniquename/spfiledbname.ora'
FROM PFILE='?/dbs/initdbname.ora'
```
If you use raw storage, then use the following syntax to create the server parameter file on a raw device:
```
CREATE SPFILE='/dev/vx/rdsk/oracle_dg/dbspfile' 
FROM PFILE='?/dbs/initdbname.ora'
```
These statements read 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.
Oracle 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/dbspfile'
```
If you use this STARTUP command syntax, then Oracle uses the server parameter file entry specified in initsid.ora.

Server Parameter File Errors in Real Application Clusters

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

Shut down the instance, recover the server parameter file, and restart the instance.
Enable 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.

See Also:

The Oracle Real Application Clusters Administrator's Guide for more information about backing up the SPFILE