Re: DASD Disk Layout Advice

From: Frank van Bortel <frank.van.bortel_at_gmail.com>
Date: Thu, 10 Dec 2009 21:02:37 +0100
Message-ID: <7b803$4b2153dd$524b9d64$9043_at_cache5.tilbu1.nb.home.nl>

joel garry wrote:
> On Nov 27, 7:45 am, Pat <pat.ca..._at_service-now.com> wrote:
>

>> 3) RAID 5 ... with todays' controllers is that getting used more
>> often? It was drilled into my head years ago that you don't put OLTP
>> data on RAID 5, but then it was drilled into my head that you never
>> mount your tablespace over NFS too and that changed :)

>
> I'm a BAARFer by nature, but I have to admit, as long as it isn't in
> degraded mode and nobody does anything stupid like yanking out two
> drives and you aren't near saturating volumes of data movement, it
> actually works pretty well on at least the specific configuration we
> have, which is quite different than yours. Just get management to at
> least agree to go away from it if some actual evidence of severe
> performance degradation occurs. I see it during mass app upgrades,
> which do things like add columns to every row in the largest tables,
> but that just is a matter of waiting until things are done.
> Performance issues during normal ops seem to skew towards cpu issues,
> for my configuration. Generally they are due to DSS type operations
> on my OLTP system. Which are decided upon by management, so are easy
> to turn around into "hardware enhancement requirements."
>
> jg
> --
> _at_home.com is bogus.
> http://failmanifesto.org/
>

Dear BAARF member # 127 (or should I say "0xFF"). One thing is still forgotten: any disk failure on a degraded RAID-5 will make your data go POOF!
Stop worrying, go SAME (Stripe And Mirror Everything, or RAID 0+1)

-- 

Regards,
Frank van Bortel (BAARF #287)

Received on Thu Dec 10 2009 - 14:02:37 CST