Re: Configuring Oracle on RAID 5

From: Fred A G <nospam_at_allowed.localhost>
Date: Tue, 13 Mar 2001 02:53:54 +0100
Message-ID: <y2fr6.1170$341.4161@nntpserver.swip.net>

""Anurag Minocha"" <aminocha_at_herold.com> wrote in message news:EBBA6D3A81229C42981E3AEA79BF5A4E111233_at_jshemail.herold.com...
> Hi,
> I was wondering that since RAID5 creates one logical volume of disk
across
> multiple drives there is no need to have multiple copies of control
files
> and also multiplexing redo logs is not required.
>

Raid protects against single-disk failures, nothing more. Have at least two or even three independent control file copies. Regarding redo log files, if you have very basic requirements (few log groups, no archiving(but why!)) then you can have only one raid-1 (mirroring) disk dedicated to redo.

> I might be wrong ... I am not sure.
>
> what care needs to be taken in creating and placing datafiles, redo
log
> files and control files on a RAID 5 machine.
> where can i find more information about Oracle on RAID 5 machines.
>

To me, this seems backward: to buy disks and other hardware and set up a Raid-5 disk array, then figure out what the database physical layout and I/O requirements are.

As a very basic setup, I'd say get at least four spindles dedicated to Oracle, one of which is for redo (two out of five, if mirroring). Maybe add one more for Oracle products software. Think IOPS, not storage volume (or, disk is cheap, don't be afraid to "waste" space). Then, if one or more datafile needs more IO put them on a Raid-5 or possibly better Raid 0+1.

Regards
/Fad Received on Mon Mar 12 2001 - 19:53:54 CST