Re: Oracle 10gR2 / RAID-5 / SAN

On Dec 20, 8:02 am, jeremy <jeremy0..._at_gmail.com> wrote:
> Hi folks
>
> Any pointers to any papers on the pros and cons of this kind of
> configuration?
>
> thanks
>
> --
> jeremy

In addition to baarf,

http://kevinclosson.wordpress.com/?s=raid
http://www.freelists.org/archives/oracle-l/10-2006/msg01134.html
http://www.thestorageforum.com/blog/index.php/2007/02/24/everything-you-know-about-disks-is-wrong/
http://www.oaktable.net/getFile/34

I've spent a lot of time on small RAID-5, and it does work. However, it is amazing how often things that are not supposed to happen do: loss of more than one disk, saturation of I/O, controller configuration issues, etc. There used to be a bunch of papers about vendors supporting small raid-5 hardware on oracle.com, when there was some initiative to push it. I had the sense that initiative was marketing-driven, something having to do with http://www.oracle.com/partners/home/why_allusers/en/benefits.html .

You should at least get a commitment to allow some other configuration for critical files that do better in other RAID configurations, should they prove to be a problem. From what I've seen, these would be serial write intensive files like redo, archived redo and backups. Also undo, simply because it is the most hit tablespace on the OLTP types of db's that I tend to work on. Since the backups and other batch type jobs tend to happen after hours, no one much cares about the I/O saturation as long as things complete in some reasonable time.

When it comes down to it, I take space over speed, if the speed isn't enough, someone else will drive the political push for it. I just make sure I'm doing the best with what I have.

jg

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