Oracle optimal flexible architecture это
This appendix describes the Optimal Flexible Architecture standard. The standard is a set of configuration guidelines created to ensure reliable Oracle installations that require little maintenance. It includes information about the following topics:
B.2 Changes to the Optimal Flexible Architecture for Oracle Database 10 g
For previous releases of Oracle Database, the Optimal Flexible Architecture standard recommended Oracle home path was similar to the following:
For Oracle Database 10 g , the Optimal Flexible Architecture recommended Oracle home path has changed. The Optimal Flexible Architecture recommended path is now similar to the following:
In this example, type is the type of Oracle home, for example Oracle Database ( db ) or Oracle Client ( client ), and n is an optional counter. This syntax provides the following benefits:
You can install different products with the same release number in the same Oracle base directory, for example:
You can install the same product more than once in the same Oracle base directory, for example:
B.5.2 Installing a Default Optimal Flexible Architecture Database: Example
This example shows how to create all Oracle homes within one Oracle base directory.
Install any Oracle Database that supports Optimal Flexible Architecture (Oracle Database release 8.1.6 or later) on a computer with no other Oracle software installed and make sure that you accept the default settings for the Oracle home (for example, c:\oracle\ora81 ).
Install any Oracle Database in a second Oracle home accepting the default settings.
Table B-1 shows the default Optimal Flexible Architecture database settings.
Table B-1 Default Optimal Flexible Architecture Database Settings
c:\oracle\product\10.2.0 (same for all Oracle homes)
B.6.2 ORACLE_BASE Directory
On Windows, Oracle base is associated with an Oracle home directory. ORACLE_BASE is defined in the registry (for example, in HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE\KEY_ HOMENAME ).
On UNIX, ORACLE_BASE is associated with a UNIX user's environment.
B.1.1 Characteristics of an Optimal Flexible Architecture Compliant Installation
The following are the characteristics of an Oracle product installation that complies with the Optimal Flexible Architecture standard:
File system organization
The file system is organized to enable easy administration and to facilitate:
Adding data into existing databases
Distributed I/O loads
I/O loads are distributed across enough disk drives to prevent performance bottlenecks.
In most cases, you do not require new hardware to implement the Optimal Flexible Architecture standard.
Safeguards Against Drive Failures
By distributing applications across more than one drive, drive failures affect as few applications as possible.
Distribution of Oracle 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 run multiple versions of Oracle software simultaneously, enabling you to test and use a new release before retiring the previous release. Transferring to a new release 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 for each database 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 easy to distinguish from other files
Files belonging to one database are easy to distinguish from files that belong to another database
Control files, redo log files, and data files can be identified as such
The association of data file 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 either Automatic Storage Management disk groups or in raw devices.
B.4.4 ADMIN Directory
Database administration files are stored in subdirectories of ORACLE_BASE\admin\ DB_UNIQUE_NAME .
B.6 Increasing Reliability and Performance
B.6.3 Using Raw Partitions for Tablespaces
A raw partition is a portion of a physical disk that is accessed at the lowest possible level. I/O of a raw partition improves performance by approximately 5 percent to 10 percent compared to I/O of a partition containing a file system. Therefore, Oracle encourages you to use raw partitions for your tablespace files.
D.3.6 Exploiting the Optimal Flexible Architecture Structure for Oracle Files
Table D-6 describes the syntax used for identifying classes of files.
Table D-6 Directory Structure Syntax for Identifying Classes of Files
User data directories
User home directories
User application software directories
Oracle applications software subtrees
Oracle software subtrees
Oracle software subtree for release 10.2.0 products
Oracle home directories for Oracle Database 10 g
sab database administrative subtrees
sab database archived log files
Oracle data directories
sab database files
sab database redo log files
B.3.1 File Systems
This section describes the conventions for mount points.
B.3.1.1 Number of File Systems
To fully implement the Optimal Flexible Architecture recommendations for a database stored on file systems that are not striped or mirrored, you require at least three file systems located on separate physical devices.
B.3.1.2 Naming Conventions
Name all file system 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 .
B.3.1.3 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 B-1 describes the variables used in this syntax.
Table B-1 Syntax for Naming Mount Points for Very Large Databases
A mount point name
A string denoting that Oracle data is stored in this directory, for example, oradata
The value of the initialization parameter DB_NAME (typically the same as the instance SID for single-instance databases)
For example, to allocate two drives exclusively for the test database, name the mount points /u01/oradata/test and /u02/oradata/test .
B.3.3 Database File Name Extensions
In Oracle8 i release 8.1.3 and earlier releases, all database files have the same .ORA extension.
.ctl for control files
.log for log files
.dbf for data files
B.3.1 Top-Level Oracle Directory
When you install Oracle Database Optimal Flexible Architecture-compliant database, there is a top-level Oracle base directory, DRIVE_LETTER :\app\ username , where DRIVE_LETTER is the hard drive letter.
The Oracle base directory contains \ ORACLE_HOME directories, \oradata directories (for database files), \diag (for diagnostic data), \flash_recovery_area (for recovery operations), and \admin directories (for database administration files).
B.7 Comparison Between Optimal Flexible Architecture on Windows and UNIX
You implement Optimal Flexible Architecture on Windows and UNIX in the same way. However, differences exist with regard to the following:
Your UNIX operating system-specific administrator's reference for information about Optimal Flexible Architecture on UNIX
B.3.6 Exploiting the Optimal Flexible Architecture Structure for Oracle Files
Table B-6 describes the syntax used for identifying classes of files.
Table B-6 Directory Structure Syntax for Identifying Classes of Files
User data directories
User home directories
User application software directories
Oracle applications software subtrees
Oracle software subtrees
Oracle software subtree for release 10.2.0 products
Oracle home directories for Oracle Database 10 g
sab database administrative subtrees
sab database archived log files
Oracle data directories
sab database files
sab database redo log files
B.6.1 Directory Naming
Top-level names of the Optimal Flexible Architecture directory tree differ between Windows and UNIX. However, main subdirectory names and file names are the same on both operating systems.
B.4.3 ADMIN Directory
B.3.7 Optimal Flexible Architecture File Mapping
Table B-7 shows a hierarchical file mapping of a sample Optimal Flexible Architecture-compliant installation with two Oracle home directories and two databases. The database files are distributed across three mount points, /u02 , /u03 , and /u04 .
Table B-7 Hierarchical File Mapping for an Optimal Flexible Architecture Installation
This appendix describes the Optimal Flexible Architecture standard. The standard is a set of configuration guidelines created to ensure reliable Oracle installations that require little maintenance. It includes information about the following topics:
D.4.1 Disk Mirroring
You can separate and treat Oracle Database log files and database files with different levels of hardware reliability. Oracle Database log files are highly reliable to start with, because they are stored redundantly. Creating similar reliability for database files may require you to duplicate all of your data, using disk mirrors.
Disk mirroring usually involves two or more identical drives and a RAID controller. If one disk fails, then the other disks can recover data that would otherwise be lost. Using one of the disks to recover lost data may involve losing the mirror. If this happens, then you must build a new mirror.
Disk mirroring is part of some levels of Redundant Array of Independent Disks (RAID) configurations, provided by the disk controller. The RAID level determines the amount of redundancy. Some RAID levels can use the hot swapping feature, which means that you can replace a bad disk with a good one without turning off the computer or losing functionality.
B.5 Optimal Flexible Architecture and Multiple Oracle Home Configurations
The following sections describe various Optimal Flexible Architecture and multiple Oracle homes configurations.
B.4.5 ORADATA Directory
This directory structure allows for disk striping on UNIX and Windows platforms. See "Support for Symbolic Links on Windows".
B.4.2 ORACLE_HOME Directory
The ORACLE_HOME directory is located under DRIVE_LETTER:\ORACLE_BASE , where DRIVE_LETTER:\ is any hard drive, and contains subdirectories for Oracle software executables and network files.
If you install Oracle Database for Windows on a computer with no other Oracle software installed and you use default settings, then the first directory that you create is called \dbhome_1 .
D.3 Implementing Optimal Flexible Architecture
This section describes the naming strategy recommended by the Optimal Flexible Architecture standard. It contains the following sections:
B.1 Overview of the Optimal Flexible Architecture Standard
The Optimal Flexible Architecture standard is designed to:
Organize large amounts of complicated software and data on disk, to avoid device bottlenecks and poor performance
Facilitate routine administrative tasks such as software and data backup, which are often vulnerable to data corruption
Facilitate switching between multiple Oracle databases
Adequately manage and administer database growth
Help eliminate fragmentation of free space in the data dictionary, isolate other fragmentation, and minimize resource contention
Optimal Flexible Architecture is a set of guidelines that you should adopt when organizing Oracle directories and files on your computer. All Oracle components on the installation media are compliant with Optimal Flexible Architecture. This means that Oracle Universal Installer places Oracle Database components in directory locations that follow Optimal Flexible Architecture guidelines.
Although using Optimal Flexible Architecture is not a requirement, Oracle recommends that you use it if your database will grow in size, or if you plan to have multiple databases.
D.2 Changes to the Optimal Flexible Architecture for Oracle Database 10 g
For previous releases of Oracle Database, the Optimal Flexible Architecture standard recommended Oracle home path was similar to the following:
For Oracle Database 10 g , the Optimal Flexible Architecture recommended Oracle home path has changed. The Optimal Flexible Architecture recommended path is now similar to the following:
In this example, type is the type of Oracle home, for example Oracle Database ( db ) or Oracle Client ( client ), and n is an optional counter. This syntax provides the following benefits:
You can install different products with the same release number in the same Oracle base directory, for example:
You can install the same product more than once in the same Oracle base directory, for example:
B.3.2 Naming Directories
This section describes the naming conventions for directories that are compliant with the Optimal Flexible Architecture standard.
B.3.2.1 Oracle Base Directory Naming Convention
The Oracle base directory is the top-level directory for Oracle products installed by the same user. Name Oracle base directories using the syntax / pm / h / u . Table B-2 describes the variables used in this syntax.
Table B-2 Syntax for Naming Oracle Base Directories
A mount point name
A standard directory name
The name of the owner of the directory (the user running Oracle Universal Installer)
For example, /u01/app/oracle is an Oracle base directory created by the oracle user and /u01/app/applmgr is an Oracle base directory created by the applmgr user.
Placing Oracle base directories at the same level in the UNIX file system is advantageous because it enables you to refer to the collection of Oracle base directories on different mount points using a single pattern matching string, /*/app/* .
B.3.2.2 Referring to Path Names
Refer to explicit path names 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.
B.3.2.3 Oracle Home Directory Naming Convention
To help fulfill the Optimal Flexible Architecture requirement of simultaneously running multiple versions of Oracle software, install the software in a directory matching the pattern / pm / h / u /product/ v / type _[ n ] .
Table B-3 describes the variables used in this syntax.
Table B-3 Syntax for Naming Oracle Home Directories
A mount point name
A standard directory name
The name of the owner of the directory
The version of the software
The type of installation, for example Database ( db ), Client ( client ), Companion ( companion ), or CRS ( crs )
An optional counter, which enables you to install the same product more than once in the same Oracle base directory
/u01/app/oracle/product/10.2.0/db_1 indicates the Oracle home directory for the first installation of Oracle Database on this system.
/u01/app/oracle/product/10.2.0/crs indicates the Oracle home directory for Oracle Clusterware (Clusterware is required for RAC installations).
Oracle Clusterware can be installed only once on the system, so the optional counter is not required.
Set the ORACLE_HOME environment variable after installation to specify the Oracle home directory.
B.3.2.4 Naming Subdirectories
To facilitate the organization of administrative data, Oracle recommends that you store database-specific administration files in subdirectories matching the pattern / h /admin/ d / a / , where h is the Oracle base directory, d is the database name (DB_NAME), and a is a subdirectory for specific types of database administration files. Table B-4 describes the database administration file subdirectories.
Table B-4 Subdirectories for Database Administration Files
Ad hoc SQL scripts
Archived redo log files
Audit files (Set the AUDIT_FILE_DEST initialization parameter to specify the adump directory. Clean out this subdirectory periodically.)
Background process trace files
Core dump files
Scripts used to create the database
Database export files
Files recording the status and history of the database
Instance parameter files
User SQL trace files
For example, /u01/app/oracle/admin/sab/adhoc/ is the adhoc subdirectory associated with the database named sab .
D.3.1 File Systems
This section describes the conventions for mount points.
D.3.1.1 Number of File Systems
To fully implement the Optimal Flexible Architecture recommendations for a database stored on file systems that are not striped or mirrored, you require at least three file systems located on separate physical devices.
D.3.1.2 Naming Conventions
Name all file system 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 .
D.3.1.3 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 D-1 describes the variables used in this syntax.
Table D-1 Syntax for Naming Mount Points for Very Large Databases
A mount point name
A string denoting that Oracle data is stored in this directory, for example, oradata
The value of the initialization parameter DB_NAME (typically the same as the instance SID for single-instance databases)
For example, to allocate two drives exclusively for the test database, name the mount points /u01/oradata/test and /u02/oradata/test .
B.5.2 Installing a Default Optimal Flexible Architecture Database: Example 1
This example shows how to create all Oracle homes within one Oracle base directory.
Install any Oracle Database that supports Optimal Flexible Architecture (Oracle Database Release 8.1.6 or later) on a computer with no other Oracle software installed and ensure that you accept the default settings for the Oracle home (for example, c:\app\ username \product\12.1.0\dbhome_1 ).
Install any Oracle Database in a second Oracle home accepting the default settings.
Table B-1 shows the default Optimal Flexible Architecture database settings.
Table B-1 Default Optimal Flexible Architecture Database Settings
c:\app\ username (same for all Oracle homes)
c:\app\ username \product\12.1.0\dbhome_1
c:\app\ username \product\12.1.0\dbhome_2
B.4 Optimal Flexible Architecture Directory Naming Conventions
Optimal Flexible Architecture uses directory naming conventions that make it easy to identify the precise Oracle home and database name that is associated with a set of files. This section describes the naming conventions used for top-level directories of an Optimal Flexible Architecture-compliant database directory tree:
B.3.3 Database File Name Extensions
In an Optimal Flexible Architecture-compliant release, database file names have the following extensions:
.ctl for control files
.log for log files
.dbf for data files
B.6.3 Support for Symbolic Links on Windows
The goal of Optimal Flexible Architecture is to place all Oracle software under one ORACLE_BASE directory and to spread files across different physical drives as your databases increase in size.
On UNIX, although everything seems to be in one directory on the same hard drive, files can be on different hard drives if they are symbolically linked or have that directory as a mount point.
On Windows, you can use volume mount points to mount files on different hard drives to a single directory. You may have oradata directories on multiple drives, with data files in each one, on Windows version which does not support volume mount points.
Oracle recommends that you use one logical drive to store your database administration files and that you place other files, as needed, on other logical drives in an oradata\ DB_UNIQUE_NAME directory.
In the following example, there are four logical drives for a database named prod :
c:\ contains an Oracle home and database administration files.
f:\ contains redo log files. The F:\ drive could also represent two physical drives that have been striped to increase performance.
g:\ contains one of the control files and all tablespace files. The G:\ drive could also use a RAID Level-5 configuration to increase reliability.
h:\ contains the second control file.
The directory structure would look similar to this:
D.1 Overview of the Optimal Flexible Architecture Standard
The Optimal Flexible Architecture standard is designed to:
Organize large amounts of complicated software and data on disk, to avoid device bottlenecks and poor performance
Facilitate routine administrative tasks such as software and data backup, which are often vulnerable to data corruption
Facilitate switching between multiple Oracle databases
Adequately manage and administer database growth
Help eliminate fragmentation of free space in the data dictionary, isolate other fragmentation, and minimize resource contention
Optimal Flexible Architecture is a set of guidelines that you should adopt when organizing Oracle directories and files on your computer. All Oracle components on the installation media are compliant with Optimal Flexible Architecture. This means that Oracle Universal Installer places Oracle Database components in directory locations that follow Optimal Flexible Architecture guidelines.
Although using Optimal Flexible Architecture is not a requirement, Oracle recommends that you use it if your database will grow in size, or if you plan to have multiple databases.
B.4.1 ORACLE_BASE Directory
ORACLE_BASE is the root of the Oracle directory tree. If you install an Optimal Flexible Architecture-compliant database using Oracle Universal Installer default settings, then ORACLE_BASE is SYSTEM_DRIVE :\oracle\product\10.2.0 .
If you are installing Oracle Database for Microsoft Windows on a computer with no other Oracle software installed, then you can change the ORACLE_BASE directory before running Oracle Universal Installer. Most users will not need or want to do this.
Do not change the value of ORACLE_BASE after you run Oracle Universal Installer for the first time. If there is an existing ORACLE_BASE and you change it, then there will be a conflict of Oracle base directories. If you create another ORACLE_BASE when the original ORACLE_BASE already exists, then certain tools and the database will not be able to find previously created files. They will look for them in the new ORACLE_BASE instead of the original ORACLE_BASE .
Your operating system documentation for instructions about editing environment variables
B.3.1 Top-Level Oracle Directory
In an Oracle8 i release 8.1.3 or earlier release, all subdirectories are located under a top-level ORACLE_HOME directory that by default is c:\orant .
When you install an Oracle8 i release 8.1.4 or later Optimal Flexible Architecture-compliant database, all subdirectories are no longer under a top-level ORACLE_HOME directory. There is now a new top-level Oracle base directory of the form DRIVE_LETTER :\oracle\product\10.2.0 , where DRIVE_LETTER is any hard drive.
The Oracle base directory contains \ ORACLE_HOME directories, \oradata directories (for database files), \flash_recovery_area (for recovery operations), and \admin directories (for database administration files).
B.3 Directory Tree Differences by Release
Optimal Flexible Architecture has necessitated changes to the Oracle Database directory tree. This section lists the differences:
B.1.1 Advantages of Multiple Oracle Homes and OFA
When you install Oracle Database, you are installing one of the largest applications that your computer can support. Using multiple Oracle homes and Optimal Flexible Architecture provides many advantages when administering large databases. The following advantages are important:
Structured organization of directories and files, and consistent naming for database files simplify database administration.
Distribution of I/O across multiple disks prevents performance bottlenecks caused by multiple read or write commands issued simultaneously to a single drive.
Distribution of applications across multiple disks safeguards against database failures.
Login home directories are not at risk when database administrators add, move, or delete Oracle home directories.
Multiple databases, of different versions, owned by different users can coexist concurrently.
Software upgrades can be tested in an Oracle home in a separate directory from the Oracle home where your production database is located.
D.3.3 Naming Database Files
The following table lists the recommended file naming conventions for database files:
File Type | File Naming Convention |
---|---|
Control files | / pm / q / d /control.ctl |
Redo log files | / pm / q / d /redo n .log |
Data files | / pm / q / d / tn .dbf |
Variable | Description |
---|---|
pm | A mount point name described previously in this appendix |
q | A string (typically oradata ) distinguishing Oracle data from all other files |
d | The value of the DB_NAME initialization parameter (typically, the same as 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 data files associated with database d in the path / pm / q / d .
Using this convention, it is easy to determine the database to which the /u03/oradata/sab/system01.dbf file belongs.
B.6.1 Disk Mirroring
You can separate and treat Oracle Database log files and database files with different levels of hardware reliability. Oracle Database log files are highly reliable because they are stored redundantly. Creating similar reliability for database files may require you to duplicate all of your data, using disk mirrors.
Disk mirroring usually involves two or more identical drives and either a hardware controller or Windows Disk Administrator. If one disk fails, then the other disks can recover data that would otherwise be lost. Using one of the disks to recover lost data may involve "breaking" the mirror. When the mirror breaks, you must build a new mirror.
Disk mirroring is part of some levels of Redundant Array of Independent Disks (RAID) configurations, provided by the disk controller. The RAID level determines the amount of redundancy. Some RAID levels can use the "hot swapping" feature, which means that you can replace a bad disk with a good one without turning off the computer or losing functionality.
B.5.1 Specifying an ORACLE_HOME Directory
To install an Optimal Flexible Architecture-compliant database, you must specify an Oracle home directory in the form of:
DRIVE_LETTER:\ is any hard drive. For example, c:\
\app\ username is the ORACLE_BASE before performing the installation.
dbhome_1 is the default directory name.
The following are examples of Optimal Flexible Architecture-compliant Oracle home directories:
B.2 Changes to the Optimal Flexible Architecture for Oracle Database 10 g
For previous releases of Oracle Database, the Optimal Flexible Architecture recommended Oracle home path was similar to the following:
In Oracle Database 10 g release 1 (10.1), the Optimal Flexible Architecture recommended Oracle home path changed. The Optimal Flexible Architecture recommended path is now similar to the following:
In this example, type is the type of Oracle home, for example Oracle Database ( database ) or Oracle Database Client ( client ), and n is an optional counter. This syntax provides the following benefits:
You can install different products with the same release number in the same Oracle base directory, for example:
You can install the same product more than once in the same Oracle base directory, for example:
B.7.2 ORACLE_BASE Directory
On Windows, ORACLE_BASE is associated with an Oracle home directory. ORACLE_BASE is defined in the registry (for example, in HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE\KEY_ HOME_NAME ).
On UNIX, ORACLE_BASE is associated with a UNIX user's environment.
B.4.3 Automatic Diagnostic Repository (ADR) Directory
Oracle Database 11 g onwards, Automatic Diagnostic Repository directories replace the bdump , cdump , and udump directories for the database. The diagnostic data goes into ORACLE_BASE \diag\rdbms\ DB_UNIQUE_NAME \instance_name
B.5 Optimal Flexible Architecture and Multiple Oracle Home Configurations
The following sections describe various Optimal Flexible Architecture and multiple Oracle homes configurations.
B.1.1 Characteristics of an Optimal Flexible Architecture-Compliant Installation
An Optimal Flexible Architecture-compliant database has the following characteristics:
Categories of files are separated into independent subdirectories so that files in one category are minimally affected by operations on files in other categories.
Consistent naming conventions for database files
Database files are easily distinguishable from all other files. Files of one database are easily distinguishable from files of another database. Data files, redo log files , and control files are easily identifiable. Data f iles are clearly associated with a particular tablespace .
Integrity of Oracle home directories
You can add, move, or delete Oracle home directories without having to revise applications that refer to them.
Separation of administrative information for each database
The ability to distinguish administrative information about one database from that of another ensures a reasonable structure for the organization and storage of administrative data.
Separation of tablespace contents
Tablespace free space fragmentation and I/O request contention are minimized, while administrative flexibility is maximized.
Tuning I/O loads across all disks
I/O loads are tuned across all disks, including disks storing Oracle data in raw devices, if needed.
B.5.4 Installing a Nondefault Optimal Flexible Architecture Database: Example 2
In this example, you install each Oracle home into its own directory, but they all share the same Oracle base.
Install any Oracle Database that supports Optimal Flexible Architecture (Oracle Database 8.1.6 or later) on a computer with no other Oracle software installed and change the default Oracle Universal Installer settings for the first Oracle home (for example, from c:\oracle\ora81 to X:\xyz\oracle\abc ).
Install any Oracle Database and change the default Oracle Universal Installer settings for the second Oracle home (for example, from c:\oracle\ora10 to X:\pqr ).
Table B-3 shows the nondefault Optimal Flexible Architecture database settings for this example.
Table B-3 Nondefault Optimal Flexible Architecture Database Settings: Example 2
(same for both Oracle homes)
The resulting directory tree would look similar to this:
B.5.3 Installing a Nondefault Optimal Flexible Architecture Database: Example 2
In this example, you install each Oracle home into its own directory, but they all share the same Oracle base.
Install any Oracle Database that supports Optimal Flexible Architecture (Oracle Database 8.1.6 or later) on a computer with no other Oracle software installed and change the default Oracle Universal Installer settings for the first Oracle home (for example, from c:\oracle\ora81 to X:\xyz\oracle\abc ).
Install any Oracle Database and change the default Oracle Universal Installer settings for the second Oracle home (for example, from c:\oracle\ora10 to X:\pqr ).
Table B-2 shows the nondefault Optimal Flexible Architecture database settings for this example.
Table B-2 Nondefault Optimal Flexible Architecture Database Settings: Example 2
(same for both Oracle homes)
The resulting directory tree would look similar to this:
B.1 Overview of the Optimal Flexible Architecture Standard
The Optimal Flexible Architecture standard is a set of file naming and configuration guidelines created to ensure reliable Oracle installations that require little maintenance.
When you install Oracle Database, you are installing one of the largest applications that your computer can support. Using multiple Oracle homes and Optimal Flexible Architecture provides many advantages when administering large databases. The Optimal Flexible Architecture standard is designed to:
Organize large amounts of complicated software and data on disk, to avoid device bottlenecks and poor performance
Facilitate routine administrative tasks such as software and data backup, which are often vulnerable to data corruption
Facilitate switching among multiple Oracle databases
Adequately manage and administer database growth
Help eliminate fragmentation of free space in the data dictionary, isolate other fragmentation, and minimize resource contention
You can think of Optimal Flexible Architecture as a set of good habits to adopt when organizing Oracle directories and files on your computer. All Oracle components on the installation media are Optimal Flexible Architecture-compliant; that is, Oracle Universal Installer places Oracle components in directory locations that follow Optimal Flexible Architecture guidelines. Although using Optimal Flexible Architecture is not a requirement, Oracle recommends that you use it if your database will grow in size, or if you plan to have multiple databases.
The goal of Optimal Flexible Architecture is to prevent an entire class of problems that can occur when you have different releases of Oracle software and multiple, growing databases on your computer.
Oracle Universal Installer separates Oracle software executables from database files. Previously, database files were placed in ORACLE_HOME \database , a subdirectory of the Oracle home directory that also contained Oracle software.
Using Optimal Flexible Architecture, Oracle Universal Installer puts Oracle software in ORACLE_BASE \ ORACLE_HOME and database files in ORACLE_BASE \oradata . When you upgrade a database to the latest release, the new Oracle software executables will be placed in a different Oracle home directory. After you judge the upgrade as successful, you can remove the old Oracle home directory and reclaim space, because the database does not reside there.
B.3.2 Database File Names
Database files do not have the SID in the database file name. For example, the first control file is named control01.ctl . The SID in the file name is not necessary because all the database files for a particular database are placed in \oradata under a directory called DB_UNIQUE_NAME that is named for that database.
B.4.6 RECOVERY_AREA Directory
The recovery_area directory stores and manages files related to backup and recovery. It contains a subdirectory for each database on the system. A fast recovery area is an optional disk location that you can use to store recovery-related files such as control files and online redo log copies, archived logs, flashback logs, and Oracle Database Recovery Manager (RMAN) backups. Oracle and RMAN manage the files in the fast recovery area automatically.
B.2 Changes to the Optimal Flexible Architecture for Oracle Database
The Optimal Flexible Architecture recommended Oracle home path is similar to the following:
The ORACLE_BASE default does not contain version information but the default ORACLE_HOME does.
B.3.5 Naming Tablespaces
Name tablespaces descriptively using a maximum of eight characters. Although Oracle Database tablespace names can be 30 characters long, portable UNIX file names are restricted to 14 characters. The recommended standard for a data file basename is tn .dbf , where t is a descriptive tablespace name and n is a two-digit string. Because the extension and the two-digit string take six characters, only eight characters remain for the tablespace name.
Descriptive names enable the data file 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 General Ledger indexes, respectively.
Do not embed reminders of the word "tablespace" in your tablespace names. Tablespace names can be distinguished by context. For example, do not name the General Ledger tablespace GLD_TBS01.dbf .
B.3.4 Separating Segments with Different Requirements
Separate groups of segments with different lifespans, I/O request demands, and backup frequencies across different tablespaces.
Table B-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.
Oracle Database Administrator's Guide for information about creating databases manually
Table B-5 Special Tablespaces
The EXAMPLE tablespace used to store the Sample Schemas
Auxiliary tablespace to the SYSTEM tablespace
Data dictionary segments
Used by Oracle to store undo information
Miscellaneous user segments
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.
D.4 Improving Reliability and Performance
One of the goals of Optimal Flexible Architecture is to improve reliability and performance by distributing I/O loads across different physical drives. The following are methods to accomplish this:
B.6.2 Disk Striping
How you set up disks for use in a database depends on the number of disks and the type of hard disk controllers available. If the hard disk controllers support both striping and mirroring, then Oracle recommends you configure the controllers to support striping.
You can configure some controllers at system startup time by issuing a keyboard sequence that brings up configuration programs written by the controller manufacturer. One goal is to stripe as many drives together as possible by configuring the controllers. Each stripe shows up as one logical device.
Striping provides significant performance advantages. All the space from the striped drives appears as a single logical drive. Furthermore, the space is used by interlacing "stripes" of space from all of the disks in the stripe. This means that a large file uses some space from the first disk, then some from the second disk and so on to the last disk, and then starting back at the first disk again. Each file can be spread over all of the striped disks. Multiple CPUs can access data randomly in such a file without contention.
Controllers that support striping usually provide caching as well. This means that data can be written to the controller, and cached and saved for a time in storage not on the disk. Data that is read can be cached on the controller in a similar fashion. Read caching should not be used with Oracle Database, because all database reads are cached already in the System Global Area (SGA). The value of parameter DB_CACHE_SIZE in the initialization parameter file ( init.ora ) determines the buffer size that can be used in the SGA. This value also configures Oracle Database on startup.
Read caching should be disabled.
Disk write caching should be disabled on disks containing Oracle data files and redo log files where the contents of the write cache are not flushed to disk on power failures or operating system failure. Consult your vendor documentation for additional information.
B.4.2 ORACLE_HOME Directory
The \ORACLE_HOME directory is located under SYSTEM_DRIVE:\ORACLE_BASE , where is any hard drive, and contains subdirectories for Oracle software executables and network files.
If you install Oracle Database for Windows on a computer with no other Oracle software installed and you use default settings, then the first Oracle home directory that you create is called \db_1 .
B.4.5 FLASH_RECOVERY_AREA Directory
The flash_recovery_area directory stores and manages files related to backup and recovery. It contains a subdirectory for each database on the system. A flash recovery area is an optional disk location that you can use to store recovery-related files such as control files and online redo log copies, archived logs, flashback logs, and Oracle Database Recovery Manager (RMAN) backups. Oracle and RMAN manage the files in the flash recovery area automatically.
Oracle Database Backup and Recovery Basics to learn how to create and use a flash recovery area
B.6 Comparison Between Optimal Flexible Architecture on Windows and UNIX
You implement Optimal Flexible Architecture on Windows and UNIX in the same way. However, differences exist regarding the following:
Your UNIX operating system-specific administrator's reference for information about Optimal Flexible Architecture on UNIX
B.7.1 Directory Naming
Top-level names of the Optimal Flexible Architecture directory tree differ between Windows and UNIX. However, main subdirectory names and file names are the same on both operating systems.
B.7 Optimal Flexible Architecture Structure File Mapping
Table B-3 shows a hierarchical file mapping for log files of a sample Optimal Flexible Architecture-compliant installation in the orcl database.
Table B-3 H ierarchical File Mapping for Log Files in an Optimal Flexible Architecture Installation
C:\app\ username \admin\orcl\TAR
Subtree for support log files
C:\app\ username \admin\orcl\arch
Archived log files
C:\app\ username \admin\orcl\create\
Contains the database creation log files
C:\app\ username \oradata\orcl\*.log
C:\app\ username \admin\orcl\dpdump\
Contains the data pump file dp.log
C:\app\ username \diag
Contains all database, listener, sqlnet and other diagnostic logs
C:\app\ username \audit
Contains all audit logs
C:\app\ username \cfgtoollogs
Contains logs for configuration assistants such as Oracle Database Configuration Assistant, Database Upgrade Assistant, and Oracle Net Configuration Assistant
This appendix describes the Optimal Flexible Architecture (OFA) standard. This standard is a set of configuration guidelines created to ensure well organized Oracle installations that are easier to maintain. It includes information about the following topics:
F.1 Overview of the Optimal Flexible Architecture Standard
The Optimal Flexible Architecture standard helps you to organize database software and configure databases to allow multiple databases, of different versions, owned by different users to coexist. Optimal Flexible Architecture assists in identification of ORACLE_BASE with its Automatic Diagnostic Repository (ADR) diagnostic data to properly collect incidents.
All Oracle components on the installation media are compliant with Optimal Flexible Architecture. Oracle Universal Installer places Oracle Database components in directory locations, assigning the default permissions that follow Optimal Flexible Architecture guidelines.
Oracle recommends that you use Optimal Flexible Architecture, especially if the database is huge, or if you plan to have multiple databases.
D.4.2 Disk Striping
How you set up disks for use in a database depends on the number of disks and the type of hard disk controllers available. If the hard disk controllers support both striping and mirroring, then Oracle recommends that you configure the controllers to support striping.
Striping provides significant performance advantages. All the space from the striped drives appears as a single logical drive. In addition, the space is used by interlacing stripes of space from all of the disks in the stripe. This means that a large file uses some space from the first disk, then some from the second disk, and so on to the last disk, and then starting back at the first disk again. Each file can be spread over all of the striped disks. Multiple CPUs can access data randomly in such a file without contention.
Controllers that support striping usually provide caching as well. This means that data can be written to the controller and cached and saved for a time in storage not on the disk. Data that is read can be cached on the controller in the same manner. Read caching should not be used with Oracle Database, because all database reads are already cached in the System Global Area (SGA). The value of the DB_CACHE_SIZE parameter in the initialization parameter file, init.ora , determines the buffer size that can be used in the SGA. This value also configures Oracle Database on startup.
Read caching should be disabled.
Disk write caching should be disabled on disks containing Oracle Database data files and redo log files where the contents of the write cache are not flushed to disk in the event of a power failure or operating system failure. Consult your vendor documentation for more information.
This appendix describes the Optimal Flexible Architecture standard. This standard is a set of configuration guidelines created to ensure well organized Oracle installations that are easier to maintain. It includes information about the following topics:
D.3.4 Separating Segments with Different Requirements
Separate groups of segments with different lifespans, I/O request demands, and backup frequencies across different tablespaces.
Table D-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.
Oracle Database Administrator's Guide for information about creating databases manually
Table D-5 Special Tablespaces
The EXAMPLE tablespace used to store the Sample Schemas
Auxiliary tablespace to the SYSTEM tablespace
Data dictionary segments
Used by Oracle to store undo information
Miscellaneous user segments
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.
D.3.7 Optimal Flexible Architecture File Mapping
Table D-7 shows a hierarchical file mapping of a sample Optimal Flexible Architecture-compliant installation with two Oracle home directories and two databases. The database files are distributed across three mount points, /u02 , /u03 , and /u04 .
Table D-7 Hierarchical File Mapping for an Optimal Flexible Architecture Installation
User data mount point 1
Subtree for application software
Oracle Base directory
Subtree for database administration files
Subtree for support log files
admin subtree for db_name1 database
admin subtree for db_name2 database
Subtree for recovery files
Recovery files for db_name1 database
Recovery files for db_name2 database
Oracle home directory for Oracle9 i release 2 (9.2.0)
Oracle home directory for Oracle Database 10 g release 2 (10.2)
Oracle base directory for user kjf
Oracle base directory for user edm
User data mount point 2
Subtree for Oracle data
Subtree for db_name1 database files
Subtree for db_name2 database files
User data mount point 3
Subtree for Oracle data
Subtree for db_name1 database files
Subtree for db_name2 database files
User data mount point 4
Subtree for Oracle data
Subtree for db_name1 database files
Subtree for db_name2 database files
F.2 Understanding Optimal Flexible Architecture
This section describes the naming strategy recommended by the Optimal Flexible Architecture standard. It contains the following sections:
This appendix describes the Optimal Flexible Architecture (OFA) standard:
D.1.1 Characteristics of an Optimal Flexible Architecture Compliant Installation
The following are the characteristics of an Oracle product installation that complies with the Optimal Flexible Architecture standard:
File system organization
The file system is organized to enable easy administration and to facilitate:
Adding data into existing databases
Distributed I/O loads
I/O loads are distributed across enough disk drives to prevent performance bottlenecks.
In most cases, you do not require new hardware to implement the Optimal Flexible Architecture standard.
Safeguards Against Drive Failures
By distributing applications across more than one drive, drive failures affect as few applications as possible.
Distribution of Oracle 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 run multiple versions of Oracle software simultaneously, enabling you to test and use a new release before retiring the previous release. Transferring to a new release 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 for each database 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 easy to distinguish from other files
Files belonging to one database are easy to distinguish from files that belong to another database
Control files, redo log files, and data files can be identified as such
The association of data file 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 either Automatic Storage Management disk groups or in raw devices.
D.3.2 Naming Directories
This section describes the naming conventions for directories that are compliant with the Optimal Flexible Architecture standard.
D.3.2.1 Oracle Base Directory Naming Convention
The Oracle base directory is the top-level directory for Oracle products installed by the same user. Name Oracle base directories using the syntax / pm / h / u . Table D-2 describes the variables used in this syntax.
Table D-2 Syntax for Naming Oracle Base Directories
A mount point name
A standard directory name
The name of the owner of the directory (the user running Oracle Universal Installer)
For example, /u01/app/oracle is an Oracle base directory created by the oracle user and /u01/app/applmgr is an Oracle base directory created by the applmgr user.
Placing Oracle base directories at the same level in the UNIX file system is advantageous because it enables you to refer to the collection of Oracle base directories on different mount points using a single pattern matching string, /*/app/* .
D.3.2.2 Referring to Path Names
Refer to explicit path names 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.
D.3.2.3 Oracle Home Directory Naming Convention
To help fulfill the Optimal Flexible Architecture requirement of simultaneously running multiple versions of Oracle software, install the software in a directory matching the pattern / pm / h / u /product/ v / type _[ n ] .
Table D-3 describes the variables used in this syntax.
Table D-3 Syntax for Naming Oracle Home Directories
A mount point name
A standard directory name
The name of the owner of the directory
The version of the software
The type of installation, for example Database ( db ), Client ( client ), Companion ( companion ), or CRS ( crs )
An optional counter, which enables you to install the same product more than once in the same Oracle base directory
/u01/app/oracle/product/10.2.0/db_1 indicates the Oracle home directory for the first installation of Oracle Database on this system.
/u01/app/oracle/product/10.2.0/crs indicates the Oracle home directory for Oracle Clusterware (Clusterware is required for RAC installations).
Oracle Clusterware can be installed only once on the system, so the optional counter is not required.
Set the ORACLE_HOME environment variable after installation to specify the Oracle home directory.
D.3.2.4 Naming Subdirectories
To facilitate the organization of administrative data, Oracle recommends that you store database-specific administration files in subdirectories matching the pattern / h /admin/ d / a / , where h is the Oracle base directory, d is the database name (DB_NAME), and a is a subdirectory for specific types of database administration files. Table D-4 describes the database administration file subdirectories.
Table D-4 Subdirectories for Database Administration Files
Ad hoc SQL scripts
Archived redo log files
Audit files (Set the AUDIT_FILE_DEST initialization parameter to specify the adump directory. Clean out this subdirectory periodically.)
Background process trace files
Core dump files
Scripts used to create the database
Database export files
Files recording the status and history of the database
Instance parameter files
User SQL trace files
For example, /u01/app/oracle/admin/sab/adhoc/ is the adhoc subdirectory associated with the database named sab .
B.3 Implementing Optimal Flexible Architecture
This section describes the naming strategy recommended by the Optimal Flexible Architecture standard. It contains the following sections:
B.5.1 Specifying an ORACLE_HOME Directory
To install an Optimal Flexible Architecture-compliant database, you must specify an Oracle home directory in the Path field of Oracle Universal Installer. It is of the form:
SYSTEM_DRIVE:\ is any hard drive. For example, c:\
PATHNAME is an optional directory path name.
\oracle is a mandatory directory path name, unless you changed the value of registry key ORACLE_BASE before performing the installation.
ORACLE_HOME is the name of the Oracle home.
The following are examples of Optimal Flexible Architecture-compliant Oracle home directories:
B.5.3 Installing a Nondefault Optimal Flexible Architecture Database: Example 1
In this example, you install Oracle Database so that each Oracle home has its own Oracle base.
Install any Oracle Database that supports Optimal Flexible Architecture (Oracle Database 8.1.6 or later) on a computer with no other Oracle software installed and change the default Oracle Universal Installer settings for the first Oracle home (for example, from c:\oracle\ora81 to X:\xyz ).
Install any Oracle Database (for example, Oracle Database 10 g release 1 (10.2)) in a second Oracle home and change the default Oracle Universal Installer settings for the second Oracle home (for example, from X:\xyz to Y:\abc ).
Table B-2 shows the nondefault Optimal Flexible Architecture database settings for example 1.
Table B-2 Nondefault Optimal Flexible Architecture Database Settings: Example 1
X:\xyz for first Oracle home; Y:\abc for second Oracle home
The resulting directory tree would look similar to this:
B.4 Optimal Flexible Architecture Directory Naming Conventions
Optimal Flexible Architecture uses directory naming conventions that make it easy to identify the precise Oracle home and database name that is associated with a set of files. This section describes the naming conventions used for top-level directories of an Optimal Flexible Architecture-compliant database directory tree:
B.7.3 Support for Symbolic Links on Windows
The goal of Optimal Flexible Architecture is to place all Oracle software under one ORACLE_BASE directory and to spread files across different physical drives as your databases increase in size.
On UNIX, although everything seems to be in one directory on the same hard drive, files can be on different hard drives if they are symbolically linked or have that directory as a mount point.
Windows currently does not support symbolic links, so data files will not show up under a single directory as with UNIX. Instead, you may have oradata directories on multiple drives, with data files in each one. This way, you get Optimal Flexible Architecture benefits, even though data files are not all visible in a single directory.
Oracle recommends that you use one logical drive to store your database administration files and that you place other files, as needed, on other logical drives in an oradata\ DB_NAME directory.
In the following example, there are four logical drives for a database named prod :
c:\ contains an Oracle home and database administration files.
f:\ contains redo log files. The F:\ drive could also represent two physical drives that have been striped to increase performance.
g:\ contains one of the control files and all tablespace files. The G:\ drive could also use a RAID Level-5 configuration to increase reliability.
B.4.1 ORACLE_BASE Directory
ORACLE_BASE is the root of the Oracle directory tree. If you install an Optimal Flexible Architecture-compliant database using Oracle Universal Installer default settings, then ORACLE_BASE is DRIVE_LETTER : \app\ username.
If you are installing Oracle Database for Microsoft Windows on a computer with no other Oracle software installed, then you can change the ORACLE_BASE directory before running Oracle Universal Installer. Most users do not need or want to do this.
Do not change the value of ORACLE_BASE after you run Oracle Universal Installer for the first time. If there is an existing ORACLE_BASE and you change it, then there is a conflict of Oracle base directories. If you create another ORACLE_BASE when the original ORACLE_BASE exists, then certain tools and the database are not able to find previously created files. They look for them in the new ORACLE_BASE instead of the original ORACLE_BASE .
Your operating system documentation for instructions about editing environment variables
B.1 Overview of the Optimal Flexible Architecture Standard
The Optimal Flexible Architecture standard helps you to organize database software and configure databases to allow multiple databases, of different versions, owned by different users to coexist. Optimal Flexible Architecture assists in identification of ORACLE_BASE with its Automatic Diagnostic Repository () diagnostic data to properly collect incidents.
All Oracle components on the installation media are compliant with Optimal Flexible Architecture. Oracle Universal Installer places Oracle Database components in directory locations, assigning the default permissions that follow Optimal Flexible Architecture guidelines.
Oracle recommends that you use Optimal Flexible Architecture, specially if the database grows in size, or if you plan to have multiple databases.
D.3.5 Naming Tablespaces
Name tablespaces descriptively using a maximum of eight characters. Although Oracle Database tablespace names can be 30 characters long, portable UNIX file names are restricted to 14 characters. The recommended standard for a data file basename is tn .dbf , where t is a descriptive tablespace name and n is a two-digit string. Because the extension and the two-digit string take six characters, only eight characters remain for the tablespace name.
Descriptive names enable the data file 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 General Ledger indexes, respectively.
Do not embed reminders of the word "tablespace" in your tablespace names. Tablespace names can be distinguished by context. For example, do not name the General Ledger tablespace GLD_TBS01.dbf .
F.1.1 Advantages of Multiple Oracle Homes and OFA
When you install Oracle database, you are installing a large application that your computer can support. Using multiple Oracle homes and Optimal Flexible Architecture provides many advantages when administering large databases. The following advantages are important:
Structured organization of directories and files, and consistent naming for database files simplify database administration.
Distribution of I/O across multiple disks prevents performance bottlenecks caused by multiple read or write commands issued simultaneously to a single drive.
Distribution of applications across multiple disks safeguards against database failures.
Login home directories are not at risk when database administrators add, move, or delete Oracle home directories.
Multiple databases, of different versions, owned by different users can coexist concurrently.
Software upgrades can be tested in an Oracle home in a separate directory from the Oracle home where your production database is located.
B.3.2 Database File Names
In Oracle8 i release 8.1.3 and earlier releases, database files have the SID in the database file name. For example, the first control file is named ctl1 SID .ora .
Beginning with Oracle8 i release 8.1.4, database files no longer have the SID in the database file name. For example, the first control file is named control01.ctl. There is no need for the presence of the SID in the file name, because all the database files for a particular database are placed in \oradata under a directory called DB_NAME that is named for that database.
B.3 Directory Tree Differences by Release
Optimal Flexible Architecture has necessitated changes to the Oracle Database directory tree. This section lists the differences:
B.3.3 Naming Database Files
The following table lists the recommended file naming conventions for database files:
Oracle Managed Files (OMF) and files stored in Automatic Storage Management disk groups use different naming conventions. For more information about these naming conventions, refer to the Oracle Database Administrator's Guide .
File Type | File Naming Convention |
---|---|
Control files | / pm / q / d /control.ctl |
Redo log files | / pm / q / d /redo n .log |
Data files | / pm / q / d / tn .dbf |
Variable | Description |
---|---|
pm | A mount point name described previously in this appendix |
q | A string (typically oradata ) distinguishing Oracle data from all other files |
d | The value of the DB_NAME initialization parameter (typically, the same as 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 data files associated with database d in the path / pm / q / d .
Using this convention, it is easy to determine the database to which the /u03/oradata/sab/system01.dbf file belongs.
B.4.4 ORADATA Directory
This directory structure allows for disk striping only on UNIX platforms. See "Support for Symbolic Links on Windows".
Читайте также: