Donald K. Burleson Oracle Tips

Optimal Flexible Architecture (OFA)

Optimal Flexible Architecture provides a logical physical layout for the database that helps the DBA to manage the system. In addition, a properly configured Oracle instance will minimize contention thus improving performance. Perhaps one of the most overlooked tuning option, configuration, must utilize OFA guidelines to be successful.

In accordance with Cary V. Millsap of the Oracle National Technical Response Team, the OFA process involves following 3 rules:

            1. Establish an orderly operating system directory structure in which any database file can be stored on any disk resource.

            2. Separate groups of segments (data objects) with different behavior into different  tablespaces.

            3. Maximize database reliability and performance by separating database components across different disk resources. A caveat for RAID environments, consider also spread across controller volume groups.

Minimum OFA Configuration

The minimum suggested configuration would consist of seven data areas, either disks, striped sets, RAID sets, or whatever else comes down the pike in the next few years. These areas should be as separate as possible, ideally operating off of different device controllers or channels to maximize throughput. The more heads you have moving at one time, the faster your database will be. The disk layout should minimize disk contention. For example:

·         AREA1: Oracle executables and user areas, a control file, the SYSTEM tablespace, redo logs

·         AREA2: Data-data files, a control file, tool-data files, redo logs

·         AREA3: Index-data files, a control file, redo logs

·         AREA4: Rollback segment-data files

·         AREA5: Archive log files

·         AREA6: Export Files

·         AREA7: Backup Staging

Of course, this is just a start, you mind find it wise to add more areas to further isolate large or active tables into their own areas as well as separating active index areas from each other.  Note that on a modern system this configuration may require 4-2 channel controller cards and 8 physically separable disk arrays.

Using this type of structure even on a RAID5 volume allows for a logical separation of files for ease in locating and controlling database files. For other platforms just alter the directory syntax for example on NT the "/oracle0/product/oracle/8.1.3" directory becomes "c:\oracle0\product\oracle\813\".

The above text is an excerpt from Mike Ault’s Oracle DBA Made Simple by Rampant TechPress.

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