Re: Configuring Oracle on RAID 5

Thanks to both of you, Howard & Kirt. This is the most coherent and lucid explanation I've been given on the whole subject.

"Kirt Thomas" <kremovethisspamthingthomas_at_gfsiinc.com> wrote in message news:6a8sato8jt0gt8b6940dd6iuf4rvtufkbf_at_4ax.com...
> This whole RAID thing chaps my hide :) We were in the process of
> adding disk to our AIX (SSA and FCAL) system, and so, we decided to
> look at the new 'SAN' type products - IBM has it's Shark, and there
> are several others around. All of them however use RAID 5. We
> initially decided to take a pass, but a large company that's name
> starts with H, let us have there system on 90 take it or leave it
> basis. This system had a substantial write cache (6gb), but in
> overall performance, it was 'half as fast' as our existing FCAL disk
> subsystem (at RAID 0+1). (It equalled the SSA, but these were tired
> old 6000rmp SSA drives, that were faux striped). We ended up punting
> the E7xxx from H after they could find no way to get performance up to
> snuff. I found it humorous that the sales staff refered to RAID 0+1
> as RAID 10 - (both IBM and H).
>
> I saw an interesting implementation of RAID 4 (where the parity is
> written to only one drive) at OpenWorld. They made a pretty good case
> for this, mirroring the parity drive, and caching all writes. But you
> still have a write penalty eventually, and even with a large cache, it
> must be written to disk sometime :)
>
>
> On Tue, 13 Mar 2001 23:07:19 +1100, "Howard J. Rogers"
> <howardjr_at_www.com> wrote:
>
> >
> >Nothing to do with the number of disks. If it were, RAID-0 would be
> >interesting, would it not??!
> >
> >I'm not real hot on my RAID numbers, but IIRC (and I think I do) 0 is
> >striping, 1 is mirroring (hence RAID 0+1 is striping AND mirroring), and
> >RAID-5 is striping with parity. Real RAID gurus will tell you all about
> >RAIDS 3, 4 and 6, but if you're like me, you will be asleep before
 they've
> >finished.
> >
> >The numbers don'r relate to anything very much, just the standard to
 which
> >that flavour of RAID adheres.
> >
> >Incidentally, RAID 5 works very well with 3 disks. Though, since I have
> >shares in Seagate, I think it only fair to say that more is always
 merrier.
> >
> >Regards
>
Received on Tue Mar 13 2001 - 12:16:41 CST