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Oracle9i Administrator's Reference
Release 2 ( for UNIX Systems: AIX-Based Systems, Compaq Tru64 UNIX, HP 9000 Series HP-UX, Linux Intel, and Sun Solaris
Part No. A97297-01
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Optimal Flexible Architecture

This appendix contains information on the Optimal Flexible Architecture (OFA) standard. The OFA standard is a set of configuration guidelines created to ensure fast, reliable Oracle databases that require little maintenance. This appendix contains the following sections:

Optimal Flexible Architecture

Oracle Corporation recommends that you implement the OFA standard when you install and configure Oracle9i.

OFA is designed to:

Characteristics of an OFA-Compliant Database

This section describes characteristics of a database that complies with the OFA standard.

File System Organization

The file system is organized to enable easy administration for issues such as:

  • Adding data into existing databases

  • Adding users

  • Creating databases

  • Adding hardware

Distributed I/O Loads

I/O loads are distributed across enough disk drives to prevent performance bottlenecks.

Hardware Support

In most cases, investment in new hardware is not required to take advantage of the OFA standard.

Safeguards Against Drive Failures

By distributing applications across more than one drive, drive failures affect as few applications as possible.

Distribution of Home Directories

The following items can be distributed across more than one disk drive:

  • The collection of home directories

  • The contents of an individual home directory

Integrity of Login Home Directories

You can add, move, or delete login home directories without having to revise programs that refer to them.

Independence of UNIX Directory Subtrees

Categories of files are separated into independent UNIX directory subtrees so that files in one category are minimally affected by operations on files in other categories.

Supports Concurrent Execution of Application Software

You can execute multiple versions of application software simultaneously, enabling you to test and use a new release of an application before abandoning the previous version. Transferring to a new version after an upgrade is simple for the administrator and transparent for the user.

Separates Administrative Information for Each Database

The ability to separate administrative information on one database from that of another ensures a reasonable structure for the organization and storage of administrative data.

Uses Consistent Database File Naming

Database files are named so that:

  • Database files are easily distinguishable from all other files

  • Files of one database are easily distinguishable from files of another database

  • Control files, redo log files, and datafiles are identifiable as such

  • The association of datafile to tablespace is clearly indicated

Separation of Tablespace Contents

Tablespace contents are separated to:

  • Minimize tablespace free space fragmentation

  • Minimize I/O request contention

  • Maximize administrative flexibility

I/O Loads Tuned Across All Drives

I/O loads are tuned across all drives, including drives storing Oracle data in raw devices.

Additional Benefits of OFA for Oracle9i Real Application Clusters

For Oracle9i Real Application Clusters Installations:

  • Administrative data is stored in a central location, accessible to all database administrators

  • Administrative data for a particular instance can be identified by filename

Optimal Flexible Architecture Implemented on UNIX

This section describes the naming strategy recommended by the OFA standard.

Mount Points

This section describes the naming conventions for mount points.

Create Mount Points

An Oracle9i installation requires at least two mount points: one for the software and at least one for the database files. To implement the OFA recommendations fully, Oracle9i requires at least four mount points: one for the software and at least three for database files.

Mount Point Syntax

Name all mount points using the syntax /pm, where p is a string constant and m is a unique fixed-length key (typically a two-digit number) used to distinguish each mount point. For example: /u01 and /u02, or /disk01 and /disk02.

Naming Mount Points for Very Large Databases (VLDBs)

If each disk drive contains database files from one application and there are enough drives for each database to prevent I/O bottlenecks, use the syntax /pm/q/dm for naming mount points. Table G-1 describes the variables used in this syntax.

Table G-1 Syntax for Naming Mount Points

Variable Description
pm A mount point name
q A string denoting that Oracle data is stored in this directory
dm The value of the initialization parameter DB_NAME (synonymous with the instance sid for single-instance databases)

For example, mount points named /u01/oradata/test and /u02/oradata/test allocate two drives for the Oracle test database.

Naming Directories

This section describes the naming conventions for OFA compliant directories.

Home Directory Syntax

Name home directories using the syntax /pm/h/u. Table G-2 describes the variables used in this syntax.

Table G-2 Syntax for Naming Home Directories

Variable Description
pm A mount point name
h A standard directory name
u The name of the owner of the directory

For example, /u01/app/oracle is the Oracle software owner home directory (also referred to as the Oracle base directory, the default directory used by the installer) and /u01/app/applmgr is an Oracle applications software owner home directory.

Placing home directories at the same level in the UNIX file system is advantageous because it allows the collection of applications owner login home directories on different mount points to be referred to using the single pattern matching string, /*/app/*.

Referring to Pathnames

Refer to explicit pathnames only in files designed specifically to store them, such as the password file, /etc/passwd, and the Oracle oratab file. Refer to group memberships only in the /etc/group file.

Software Directories

To help fulfill the OFA feature of simultaneously executing multiple versions of application software, store each version of the Oracle9i Server software in a directory matching the pattern /pm/h/u/product/v.

Table G-3 describes the variables used in this syntax.

Table G-3 Syntax for Naming Oracle9i Server Software Directories

Variable Description
pm A mount point name
h A standard directory name
u The name of the owner of the directory
v The version of the software

For example, /u01/app/oracle/product/ indicates the Oracle9i parent directory. Set the ORACLE_HOME environment variable to this directory.

Naming Subdirectories

To facilitate the organization of administrative data, Oracle Corporation recommends that you store database-specific administration files in subdirectories matching the pattern /h/admin/d/a/, where h is the Oracle software owner's home directory, d is the database name (DB_NAME), and a is a subdirectory for each of the database administration files. Table G-4 describes the database administration file subdirectories.

Table G-4 Subdirectories for Database Administration Files

Subdirectory Description
adhoc Ad hoc SQL scripts for a particular database
arch Archived redo log files
adump Audit files
(Set the AUDIT_FILE_DEST initialization parameter to the adump directory. Clean out this subdirectory periodically.)
bdump Background process trace files
cdump Core dump files
create Programs used to create the database
exp Database export files
logbook Files recording the status and history of the database
pfile Instance parameter files
udump User SQL trace files

For example, the adhoc subdirectory has the pathname /u01/app/oracle/admin/sab/adhoc/ if the adhoc subdirectory is part of the database named sab.

Naming Database Files

The following naming convention for database files ensures that they are easily identifiable:

File Type File Naming Convention
Control files /pm/q/d/control.ctl
Redo log files /pm/q/d/redon.log
Datafiles /pm/q/d/tn.dbf

The following table describes this syntax:

Variable Description
pm A mount point name described previously in this chapter
q A string distinguishing Oracle data from all other files (usually named ORACLE or oradata)
d The value of the initialization parameter DB_NAME (synonymous with the instance sid for single-instance databases)
t An Oracle tablespace name
n A two-digit string


Do not store files other than control files, redo log files, or datafiles associated with database d in the path /pm/q/d.

Following this convention, you could produce, for example, a datafile with the name /u03/oradata/sab/system01.dbf, making it easy to see the database to which the file belongs.

Separate Segments With Different Requirements

Separate groups of segments with different lifespans, I/O request demands, and backup frequencies across different tablespaces.

Table G-5 describes the special tablespaces that the Database Configuration Assistant creates for each Oracle database. If you manually create a database, you must create the required tablespaces. These tablespaces are in addition to those required for application segments.

See Also:

Oracle9i Database Administrator's Guide for information on creating tablespaces manually.

Table G-5 Special Tablespaces

Tablespace Required Description
CWMLITE No OLAP catalog metadata repository (CWMLite)
DEMO No Demo schema
DRSYS No Oracle Text segment
INDX No Index associated with data in the USERS tablespace
OEM_REPOSITORY No Repository for Oracle Enterprise Manager
RBS Yes Rollback segments
SYSTEM Yes Data dictionary segments
TEMP Yes Temporary segments
USERS No Miscellaneous user segments
XDB No The XDB tablespace holds the data that is stored in the Oracle XML DB repository through SQL or through protocols such as HTTP and WebDAV.

Creating these special tablespaces is effective because data dictionary segments are never dropped, and no other segments that can be dropped are allowed in the SYSTEM tablespace. Doing this ensures that the SYSTEM tablespace does not require a rebuild due to tablespace free-space fragmentation.

Because rollback segments are not stored in tablespaces holding applications data, the administrator is not blocked from taking an application's tablespace offline for maintenance. The segments are partitioned physically by type, and the administrator can record and predict data growth rates without using complicated tools.

Naming Tablespaces

Name tablespaces descriptively using a maximum of eight characters. Although Oracle9i tablespace names can be 30 characters long, portable UNIX filenames are restricted to 14 characters. The recommended standard for a datafile basename is tn.dbf, where t is a descriptive tablespace name and n is a two-digit string. Because the extension plus the two-digit string occupy a total of six characters, only eight characters remain for the tablespace name.

Descriptive names enable the datafile to be associated with the tablespace that uses it. For example, the names GLD and GLX might be used for the tablespaces storing General Ledger data and indices, respectively.


Do not embed reminders of the word "tablespace" in your tablespace names. Tablespaces are distinguishable by context, and names do not need to convey information on type.

Exploiting the OFA Structure for Oracle Files

Table G-6 describes the syntax used for identifying classes of files.

Table G-6 Directory Structure Syntax for Identifying Classes of Files

Directory Structure Syntax Description
/u[0-9][0-9] User data directories
/*/home/* User home directories
/*/app/* User application software directories
/*/app/applmgr Oracle applications software subtrees
/*/app/oracle/product Oracle software subtrees
/*/app/oracle/product/ Oracle Server release distribution files
/*/app/oracle/admin/sab sab database administrative subtrees
/*/app/oracle/admin/sab/arch/* sab database archived log files
/*/oradata Oracle data directories
/*/oradata/sab/* sab database files
/*/oradata/sab/*.log sab database redo log files

OFA File Mapping

Table G-7 shows a hierarchical file mapping of a sample OFA-compliant database, including each file mount point, application, database, and tablespace. The filenames indicate the file type (control, log, or data).

Table G-7 Hierarchical File Mapping for OFA Installation

Directory Description
Root mount point
/u01/ User data mount point 1
/u01/app/ Subtree for application software
/u01/app/oracle/ Home for oracle software user
/u01/app/oracle/admin/ Subtree for database administration files
/u01/app/oracle/admin/TAR Subtree for support log files
/u01/app/oracle/admin/db_name1/ admin subtree for db_name1 database
/u01/app/oracle/admin/db_name2/ admin subtree for db_name2 database
/u01/app/oracle/doc/ Online documentation
/u01/app/oracle/product/ Distribution files
/u01/app/oracle/product/8.1.6/ Oracle home directory for release 8.1.6 instances
/u01/app/oracle/product/8.1.7/ Oracle home directory for release 8.1.7 instances
/u01/app/oracle/product/ Oracle home directory for release instances
/u01/app/ltb/ Home directory for a user
/u01/app/sbm/ Home directory for a user
/u01/oradata/ Subtree for Oracle data
/u01/oradata/db_name1/ Subtree for db_name1 database files
/u01/oradata/db_name2/ Subtree for db_name2 database files
/u02/ User data mount point 2
/u02/home/ Subtree for login home directories
/u02/home/cvm/ Home directory for a user
/u02/home/vrm/ Home directory for a user
/u02/oradata/ Subtree for Oracle data
/u02/oradata/db_name1/ Subtree for db_name1 database files
/u02/oradata/db_name2/ Subtree for db_name2 database files
/u03/ User data mount point 3
/u03/oradata/ Subtree for Oracle data
/u03/oradata/db_name1/ Subtree for db_name1 database files
/u03/oradata/db_name2/ Subtree for db_name2 database files

File Mapping for a Multiple-Instance OFA Database

When using the Oracle9i Real Application Clusters, select one node to act as the Oracle administrative home for the cluster. The administrative home contains the administrative subtree. Create subdirectories for each instance accessing the database within the bdump, cdump, logbook, pfile, and udump directories of the ~/admin/d/ directory. Mount the admin directory for the administrative home as the admin directory for every instance. Table G-10 shows a sample directory structure.

Table G-8 Administrative Directory Structure for Dual-Instance Oracle9i Real Application Clusters

Directory Path Description
/u01/app/oracle/admin/sab/ Administrative directory for sab database
/u01/adhoc/ Directory for miscellaneous scripts
/u01/arch/ Log archive destination for all instances
/u01/arch/redo001.arc Archived redo log file
/u01/bdump/ Directory for background dump files
/u01/bdump/inst1/ Background dump destination for inst1 instance
/u01/bdump/inst2/ Background dump destination for inst2 instance
/u01/cdump/ Directory for core dump files
/u01/cdump/inst1/ Core dump destination for inst1 instance
/u01/cdump/inst2/ Core dump destination for inst2 instance
/u01/create/ Directory for creation scripts
/u01/create/1-rdbms.sql SQL script to create inst database
/u01/exp/ Directory for exports
/u01/exp/20000120full.dmp January 20, 2000 full export dump file
/u01/exp/export/ Directory for export parfiles
/u01/exp/import/ Directory for import parfiles
/u01/logbook/ Directory for logbook entries
/u01/logbook/inst1/ Directory for inst1 instance reports
/u01/logbook/inst1/params.1st V$PARAMETER report for inst1 instances
/u01/logbook/inst2/ Directory for inst2 instances reports
/u01/logbook/inst2/params.1st V$PARAMETER report for inst2 instances
/u01/logbook/user.1st DBA_USERS report
/u01/pfile/ Directory for instance parameter files
/u01/pfile/inst1/ Directory for inst1 instance parameters
/u01/pfile/inst1/initinst1.ora Instance parameters for inst1 instance
/u01/pfile/inst2/ Directory for inst2 instance parameters
/u01/pfile/inst2/initinst2.ora Instance parameters for inst2 instance
/u01/udump/ Directory for user dump files
/u01/udump/inst1/ User dump destination for inst1 instance
/u01/udump/inst2/ User dump destination for inst2 instance

Directory Structure

The following sections describe the directory structure for OFA compliant installations.

ORACLE Base Directory

The Oracle base directory is the root of the Oracle directory structure. When installing an OFA-compliant database using the Oracle Universal Installer, the default Oracle base directory is set to /pm/app/oracle. Table G-9 describes an Oracle base directory structure and content.

Table G-9 Oracle Base Directory Structure and Content

Directory Description
admin Administrative files
doc Online documentation
local Subtree for local Oracle software
product Oracle software

Oracle Home Directory

If you install an OFA-compliant Oracle Server, the Oracle home directory is /pm/app/oracle/product/release_number. Table G-10 describes the Oracle home directory structure and content. Under UNIX, the Oracle home directory contains the subdirectories described in Table G-10, as well as a subdirectory for each Oracle product installed.

Table G-10 Oracle Home Directory Structure and Content

Directory Description
assistants Configuration Assistants
bin Binaries for all products
ctx Oracle Text files
dbs Initialization files
install Installation-related files
lib Oracle product libraries
jlib Java classes
md Spatial options
mlx Xerox Stemmer (for Oracle Text files)
network Oracle Net Services files
ocommon Common files for all products
odg Data gatherer files
oracore Core libraries
ord Oracle interMedia files
otrace Oracle TRACE files
plsql PL/SQL files
precomp Precompiler files
rdbms Server files and libraries required for the database
slax SLAX parser files
sqlplus SQL*Plus files

Examples of Product Subdirectories

Table G-11 shows examples of product subdirectories and their contents.

Table G-11 Examples of Product Subdirectories

Directory Description
rdbms admin, doc, install, lib, log, mesg
sqlplus admin, demo, doc, install, lib, mesg

Contents of Product Subdirectories

Table G-12 describes the subdirectories contained in the rdbms and sqlplus product subdirectories.

Table G-12 Contents of Product Subdirectories

Directory Description
admin Administrative SQL and shell scripts (for example, catalog.sql, catexp.sql, and demo.sql)
admin/* Special directories for other products
admin/resource Resource files
admin/terminal Runtime terminal files
demo Demonstration scripts and datafiles
doc README files (for example, readmeunix.doc)
install Product installation scripts
jlib Product Java classes
lib Product libraries and distributed make files
log Trace files and log files (for example, orasrv.log and *.trc files)
mesg U.S. message files and binary files (for example, oraus.msg and oraus.msb)

File Naming Conventions in the admin Directory

Table G-13 shows the SQL scripts located in the $ORACLE_HOME/rdbms/admin directory.

Table G-13 admin Directory, File Naming Conventions

File Description
cat*.sql Creates catalog and data dictionary tables and views. The following files are run automatically during installation:
  • catalog.sql (for all installations)

  • catproc.sql (for all installations)

  • catclust.sql (for Oracle9i Real Application Clusters option installations)

  • catrep.sql (for all installations)

The catproc.sql file in turn runs the scripts for creating the standard PL/SQL packages, such as DBMS_SQL and DBMS_OUTPUT.

d*.sql Downgrade scripts
dbms*.sql Additional database packages
u*.sql Upgrade scripts
utl*.sql Creates tables and views for database utilities

Filename Extensions

Table G-14 describes filename extensions.

Table G-14 Filename Extensions

Extension Description
.a Object file libraries; Ada runtime libraries
.aud Oracle audit file
.bdf X11 font description file
.bmp X11 bitmap file
.c C source file
.ctl SQL*Loader control file; Oracle Server control file
.dat SQL*Loader datafile
.dbf Oracle Server tablespace file
.dmp Export file
.doc ASCII text file
.env Shell script file for setting environment
.h C header file; also, sr.h is a SQL*Report Writer help file
.jar Java class archive
.l UNIX manual page
.lis Output of SQL*Plus script
.log Installation log files; Oracle Server redo log file
.mk Make file
.msb Multilingual Option message file (binary)
.msg Multilingual Option message file (text)
.o Object module
.ora Oracle configuration file
.orc Installation prototype file
.pc Pro*C source file
.pco Pro*COBOL source file
.ppd Printer driver file
.sh Bourne shell script file
.sql SQL script file
.sys Bourne shell script file
.tab SQL script file
.trc Trace file
.utd Uniform Terminal Definition file
.zip Zip file

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