||Oracle Tips by Burleson
Oracle Optimal Flexible Architecture (OFA)
In accordance with Cary V. Millsap of the Oracle National Technical
Response Team, the OFA process involves the following three rules:
1. Establish an orderly operating system directory structure in
which any database file can be stored on any disk resource.
- Name all devices that might contain Oracle data in such a
manner that a wild card or similar mechanism can be used to
refer to the collection of devices as a unit.
- Make a directory explicitly for storage of Oracle data at
the same level on each of these devices.
- Beneath the Oracle data directory on each device, make a
directory for each different Oracle database on the system.
- Put a file X (X is any database file) in the directory
/u??/ORACLE/sid/type_desig (or on W2K or NT: C:\oracle\sid\type_desig)
if and only if X is a control file, redo log file, or datafile
of the Oracle database whose DB_NAME is sid. The type_desig
specifies the type of file to be placed in the directory at that
location and is usually data, index, control or redo.
You may wish to add an additional directory layer if you will have
multiple Oracle versions running at the same time. This additional
layer includes the version level.
2. Separate groups of segments (data objects) with different
behavior into different tablespaces.
- Separate groups of objects with different fragmentation
characteristics in different tablespaces (e.g., donít put data
and rollback segments together).
- Separate groups of segments that will contend for disk
resources in different tablespaces (e.g., donít put data and
- Separate groups of segments representing objects with
differing behavioral characteristics in different tablespaces
(e.g., donít put tables that require daily backup in the same
tablespace with ones that require yearly backup).
3. Maximize database reliability and performance by separating
database components across different disk resources. A caveat for
RAID environments: Consider spreading datafiles across multiple
controller volume groups.
- Keep at least three active copies of a database control file
on at least three different physical arrays.
- Use at least three groups of redo logs in Oracle. Isolate
them to the greatest extent possible on hardware serving few or
no files that will be active while the RDBMS (relational
database management system) is in use. Shadow redo logs whenever
- Separate tablespaces whose data will participate in disk
resource contention across different physical disk resources.
(You should also consider disk controller usage.)
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