Performance Requirements 

For performance reasons, each of the different types of volume should be stored on a different disk. Therefore, create data volumes and log volumes on different disks. Because all changes to the database instance are logged in the log areas , it is the log volumes for a database instance that see the most write activity.

Even when you use RAID-5 systems, configure the database instance with multiple data volumes. Performance will be better with many data volumes than with a single one, because some parallel mechanisms used by the database system depend on the number of configured data volumes.

For performance reasons, the log volumes must not be created on RAID-5 systems but only on dedicated disks or RAID-1 systems.

If swap or paging areas and log entries are kept on the same disk, performance will be negatively affected.

UNIX: Raw devices should be used for the data volumes and log volumes, because accessing to data in raw devices is generally quicker than accessing data in files.