Is the location of database files irrelevant these days when the capabilities of high end storage seems to address all possible issues?
The answer is still yes according to a good friend I was working with the last two weeks. It is extremely relevant and the performance gaining of following this rule is high, as high is the penalty for not following it.
Every production environment needs to be built according to this standard:
The formula for database location on the frame is 20%-40%-20%-20%:
- 20% of the disk located on the external cylinder is the best performing area of the frame, to be used by online redo logs, undo segments, temp segments and most accessed database files
- 40% near the external cylinder is a good performing area, to be used by all other database files
- Next 20% is a slow performing area and should not be used for database files, except parameter files, archived logs, software install
- Last 20% correspond to the inner cylinder, is the slowest performing area and should not be used for database files at all.
Lun's to be used by the database needs to be mapped to assure that the database is located in the most performing areas of your frame.
This is a task that must be accomplished working together with Storage Vendors and Storage Administrators.
If this task was not done, a mapping of the actual lun's can be requested from the vendor or storage administrator.