B Optimal Flexible Architecture

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

  • 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, 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.3.1 File Systems

This section describes the conventions for mount points.

B.3.2 Naming Directories

This section describes the naming conventions for directories that are compliant with the Optimal Flexible Architecture standard.

B.3.3 Naming Database Files

The following table lists the recommended file naming conventions for database files:

The following table describes this syntax:

Using this convention, it is easy to determine the database to which the /u03/oradata/sab/system01.dbf file belongs.

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.

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.

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.

B.3.6 Exploiting the Optimal Flexible Architecture Structure for Oracle Files

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

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.