Oracle FAQ Your Portal to the Oracle Knowledge Grid

Home -> Community -> Mailing Lists -> Oracle-L -> RE: Configuring Oracle with RAID and OFA

RE: Configuring Oracle with RAID and OFA

From: Stephane Faroult <>
Date: Thu, 27 Mar 2003 07:19:29 -0800
Message-ID: <>

>Hi all,
>I am configuring a system for use with Oracle and
>am confused on the concepts
>of RAID and OFA, specifically how they work
>I inherited a system that is a RAID 5 utilizing 5
>disks. Oracle8i (8.1.7) is
>currently running on it. The database is setup on
>one disk (data files,
>control files, redo logs, etc.).
>I understand that striping spreads the info out
>across all the disks. That
>being true, is it necessary to put the redo logs,
>rollback segments, etc on
>sepaparte disks ala OFA?
>Since the database is not in production yet, I have
>time to make these changes
>(not to mention we are planning to redo the setup
>with Red Hat Advanced
>Server and upgrade to Oracle9i).
>Thanks in advance for your help. Feel free to
>point me to additional reading
>materials that will clarify this for me.


   First I have rarely heard people enthusing about Oracle on RAID 5 ...    Standards are here more for clarity than performance. Carefully laying out your files used to have some meaning, when you knew that you had a number of separate controllers and different disks, and that this controller was managing this disk, and by assigning this file to this disk and this one to another then you could hope that both accesses could occur in parallel, or at least that they would not compete, each one trying to bring the disk heads to read or write different cylinders. Things are much much more confused these days, with memory caches everywhere, virtual disks which are indeed little pieces of actual physical disks, etc. And I don't believe that we'll ever come back to a close match between what you 'see', and the actual hardware. In fact, everything is pointing in the opposite direction.  Just remember that redo logs are written sequentially, so if the disk heads could not move frantically it would be better, and that you have several of them needing to be written at the same time. Otherwise that rollback segments/undo tablespace and temporary segments are often heavily accessed. Have a look at V$FILESTAT and then try to do for the best, with directory structures which look logical to you (and, hopefully, to others).


Stephane Faroult

Please see the official ORACLE-L FAQ:
Author: Stephane Faroult

Fat City Network Services    -- 858-538-5051
San Diego, California        -- Mailing list and web hosting services
To REMOVE yourself from this mailing list, send an E-Mail message
to: (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB ORACLE-L
(or the name of mailing list you want to be removed from).  You may
also send the HELP command for other information (like subscribing).
Received on Thu Mar 27 2003 - 09:19:29 CST

Original text of this message