EMC (was: Re: ORACLE8 NT and RAID5)

From: Harald Wakonig <wakonig_at_csi.com>
Date: Sat, 07 Aug 1999 21:54:47 +0200
Message-ID: <37AC8F07.1B128BFF@csi.com>

Hi Dough,

> > We recently had the opportunity to do some performance comparing of RAID
> > levels in a real world environment using both compaq and EMC dasd. Here
> > are the results:
> >
> > Raid Level - Cycle times
> > Raid 5 (EMC RAID S) - 23 hours
> > Raid 1 (EMC) - @12 hours
> > RAID 10 (0+1) (Compaq) - @11 hours
>

> > Doug Coan
> > Senior Client Server System Integrator
> > AEGON USA
> > dcoan_at_aegonusa.com

(1) Is it possible to configure parts of an huge EMC-system as RAID5 (RAID S) and
Parts as RAID1 ? (e.g. Data RAID5, online-redolog and temporary tablespace RAID1)
or is it necessary to buy two different products of EMC ? (Is EMC RAID S a own
product or just a configuration - option, and is it possible to configure only
one part as RAID S) ?

(2) Assuming, I can afford the additional disk space required to run Oracle only
on RAID1 instead of RAID5:
Is it possible to configure EMC that e.g. 2 filesystems DO NOT share any disks
and any controller
(e.g. Filesystem 1 for data disks 1-10 mirrored to 11-20, Filesystem 2 for online-redolog 21-22 mirrored to 23-24)

(3) I personally would not put all Oracle-Files on one RAID5-Array, but would put
at least one member of the online-redologs and the archive-logs on "normal" disks
OUTSIDE of the array, so that I could do a complete recovery even if the array
failes.....

Is this configuration usual or at least recommended in an EMC-environment
(3a) if there is just one EMC-system in the datacenter (3b) if the whole EMC-system is mirrored via fibre into a second data center?

(4) Anyone who has experience or a link to a white paper describing running
Oracle on EMC, which is on a deep technical level answering my questions ?

(4a) from a "absolutely recovery-perspective" (can one EMC-System be considered
as "Single-Point-of-Failure" - even if all disks are mirrored and don't share
controllers, the software - at least in case of RAID5 there must be some calculation which bytes are stored on which disk...) might have a bug , and
independent controllers and disk just mirror the wrong bytes...)

(4b) from an performance-perspective

(5) Is anybody aware of "official" recommendations
(a) from Oracle
(b) from EMC about running Oracle on EMC - especially from the

perspective (4a)!

Thank you for any hints...

Harald Received on Sat Aug 07 1999 - 14:54:47 CDT