Oracle Database Discussions

Hello friends,

I have a question which I have seen various points of view. I'm hoping you might be able to give me a better insight so I can either confirm my own sanity, or accept a new paradigm shift in laying out the file system for best performance.

Here are the givens:

Unix systems (AIX, HP-UX, Solaris, and/or Linux).

Hardware RAID system on large SAN (in this case, RAID-05 striped over more than 100 physical disks).
(We are using AIX 6.1 with CIO turned on for the database files).

Each Physical Volume is literally striped over at least physical 100 disks (spindles).
Each Logical Volume is also striped over at least 100 spindles (all the same spindles for each lvol).

Oracle software binaries are on their own separate physical volume.

Oracle backups, exports, flash-back-query, etc., are on their own separate physical volume.

Oracle database files, including all tablespaces, redo logs, undo ts, temp ts, and control files are in their own separate physical volume (that is made up of logical volumes that are each striped over at least 100 physical disks (spindles).

The question is if it makes any sense (and WHY) to break up the physical volume that is used for the Oracle database files themselves, into multiple logical volumes? At what point does it make sense to create individual logical volumes for each datafile, or type, or put them all in a single logical volume?

Does this do anything at all for performance? If the volumes are logical, then what difference would it to put them into individual logical volumes that are striped across the same one-hundred (+) disks?

Basically ALL database files are in a single physical volume (LUN), but does it help (and WHY) to break up the physical volume into several logical volumes for placing each of the individual data files (e.g., separating system ts, from sysaux, from temp, from undo, from data, from indexes, etc.) if the physical volume is created on a RAID-5 (or RAID-10) disk array on a SAN that literally spans across hundreds of high-speed disks?

If this does makes sense, why?

From a physical standpoint, there are only 4 hardware paths for each LUN, so what difference does it make to create multiple 'logical' volumes for each datafile, or for separating types of data files?

From an I/O standpoint, the multi-threading of the operating system should only be able to use the number of pathways that are capable based on the various operating system options (e.g., multicore CPUs using SMT (simultaneous multipath threading). But I believe they are still based on physical paths, not based on logical volumes.

I look forward to hearing back from you.

Thanks.

ji li