Re: RAIDs and Oracle Tablespace layout

In article <95uh7l$tqi$1_at_nnrp1.deja.com>,   mjgusa_at_my-deja.com wrote:
> Hello:
>
> I am implementing a system that will have a fairly large Oracle 8i
> database on a SUN system that has a RAID file system on it. I am
> wondering if, since the files are ultimately on a RAID, this spares us
> from caring about the layout of which tables/indexes go in what files
 or
> not. I am assuming that no matter what file the data/index is on, the
> stream comes from all disks anyway so there is no way to affect things
> either way by putting certain table spaces on certain disks. Does
> anyone have any experience with this?
>
> Thanks,
> Mike
>
> Sent via Deja.com
> http://www.deja.com/
>

ouch ouch ouch :-)

There have been a few spirited debates conducted here concerning RAID and disk layout. You could be in for a bit of a mess if you are not aware of the pros/cons of different raid configurations and how to lay things out. It really depends on the size of your db and just how bad the RAID is done.

I have seen bad raid layouts (multiple dbs and servers sharing physical drives and raid 5) turned into good raid layouts (raid 0+1 with dedicated physicals) and the performance improve by 10x or more.

Many of the oracle books I have seen somewhat gloss over raid, but the major disk vendors have whitepapers on how to lay out oracle on their stuff. I would put the most confidence in some of the discussions that have been held here however.

Last comment and personal opinion - NEVER EVER EVER put a database on raid 5 unless you really really really hate your clients and if you are the DBA don't mind spending all your time watching disk lights.

Good luck....

--
Doug Coan
Oracle Certified Professional DBA


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