Re: General SAN advice needed for 2TB 9.2.0.8 database on HP-UX

From: joel garry <joel-garry_at_home.com>
Date: Tue, 29 Jun 2010 13:17:24 -0700 (PDT)
Message-ID: <bfd81f02-3859-482e-ad23-8e69531f0223_at_x24g2000pro.googlegroups.com>

On Jun 29, 12:26 pm, Frank van Bortel <fbor..._at_home.nl> wrote:
> On 06/23/2010 04:07 PM, Mladen Gogala wrote:
>
> > On Wed, 23 Jun 2010 11:00:11 +0200, Frank van Bortel wrote:
>
> >> Make it all SAME: Stripe and Mirror Everything.
>
> > You're in marketing? SAME == RAID 1+0.
>
> No; and I prefer RAID 0+1.
> Not in storage, I seem to recall striping was RAID-0, mirroring
> was RAID-1. Same would be RAID-0+1, then, eh?

No, see what the faq says, and that 1+0 is better (for fault tolerance): http://www.orafaq.com/wiki/RAID

http://jonathanlewis.wordpress.com/2007/02/05/go-faster-stripes/ has some good thoughts.

>
>
>
> >> Don't know about stripe sizes -
>
> > That was the OP's question.
>
> >> what do you think to gain by playing with these?
>
> > Speed.
>
> Still, no one provided any hard numbers.
>
> Everybody seems convinced about gains in playing
> with these figures, but the question remains:
> - is 1MB stripe any different from what the
>    vendor recommended?
> - if so, what gains in speed were measured
>    ordered by stripe size?

That's the gist: measure what the real load will be doing. I'd agree with John about online logs, but most of my experience over the last decade has been with RAID-5, so I didn't say anything 'cause I really haven't looked. And yes, I'm a baarf member.

This one seems to say go coarse on the stripes: http://www.hds.com/assets/pdf/best-practices-library-deploying-oracle-11g-rac-with-hds.pdf I haven't looked at it too closely to see if it makes sense, and haven't checked whether it applies to the OP hardware. "The default stripe depth for an ASM group is 1MB, which is too low to make efficient use of the underlying RAID group stripe size. This should be set to 8MB at ASM group creation time by specifying the AU_SIZE attribute..."

jg

--
_at_home.com is bogus.
"I believe it’s horribly bad in SQL Server, but it’s doubly horribly
bad in Oracle." - Tom Kyte on triggers

Received on Tue Jun 29 2010 - 15:17:24 CDT