Optimal Flexible Architecture (OFA)

Oracle's Optimal Flexible Architecture (OFA) is the Oracle recommended, standard database layout. OFA includes three primary objectives:

• OFA establishes a directory structure into which any database file can be stored. This can facilitate use of any disk resource.

• OFA separates objects with different behaviors into different tablespaces.

• OFA maximizes database reliability, availability, and performance by separating database components across different disk resources.

The OFA directory structure is a standard set of configuration guidelines that allow for fast, reliable Oracle databases that require the minimum maintenance.

OFA is designed to assist you, as a DBA, to do the following:

• Organize a large amount of complicated software with multiple components and products.

• Organize data and control structures on disk in such a way as to avoid device bottlenecks and poor performance.

• Facilitate routine administrative tasks that are often vulnerable to data corruption.

• Adequately manage and administer database growth.

• Help minimize fragmentation of free space in the data dictionary, isolate what fragmentation might occur, and minimize resource contention.

OFA installation is supported on all platforms on which Oracle can be installed and helps you organize your database files by type of file and by usage. Binaries, data files, and supporting files can be spread across several disks, and because of naming conventions, each can easily be differentiated from the rest. Database files can easily be determined to be different from log and control files, redo log files, and trace files. Because of OFA, it is more simple and elegant to administer multiple Oracle homes on the same machine because files can be spread over multiple disks and directories. Not only is this more efficient administratively, it also means that better performance can be achieved by decreasing disk contention among the different types of files.

The directory structures in Table 2.2 show examples of what might be found in an OFA-compliant installation in both Windows and Unix environments.

Table 2.2. Example OFA Directory Structures

Unix Software	Windows Software
Oracle_base  /product    /release number      /bin      /dbs      /rdbms      /    /admin      /instance name        /adhoc        /adump        /bdump        /cdump        /create        /exp        /pfile        /udump	ORACLE_HOME   \product_release      \bin      \dbs      \rdbms      \...   \admin      \instance name         \adhoc         \adump         \bdump         \cdump         \create         \exp         \pfile         \udump
Files	Files
/oracle    /oradata        / dbname        redo01a.log        redo02a.log        redo03a.log        control03.ctl /oracle2   /oradata      /dbname        control01.ctl        index01.dbf        undo01.dbf        system01.dbf        temp01.dbf        users01.dbf        redo01b.log        redo02b.log        redo03b.log /oracle3    /oradata       / dbname          control02.ctl          redo01c.log          redo02c.log          redo03c.log	F:\oracle    \oradata       \prod       redo01a.log       redo02a.log       redo03a.log       control03.ctl G:\oracle   \oradata      \prod         control01.ctl         indx01.dbf         undo01.dbf         system01.dbf         temp01.dbf         users01.dbf         redo01b.log         redo02b.log         redo03b.log H:\oracle    \oradata       \prod          control02.ctl          redo01c.log          redo02c.log          redo03c.log

It is important, when installing with OFA in mind, that you organize the file system so that you can more easily administer growth by adding data into existing databases, adding users, and creating new databases. What's more, you need to consider the ramifications of later adding hardware so that you can easily and elegantly distribute the I/O load across all available drives and devices.

Your database's security is vital, and regardless of what interface you use to access your databases, authentication is uppermost in the minds of most DBAs. The following section deals with Oracle 9i's capability to address many of these security concerns.