Re: New Disk Setup

From: <lpellecc_at_gmail.com>
Date: Thu, 28 May 2009 05:58:22 -0700 (PDT)
Message-ID: <f11e9de4-9ae9-4b67-bf4f-a2eb52ee82db_at_u10g2000vbd.googlegroups.com>



On May 28, 7:55 am, johnbhur..._at_sbcglobal.net wrote:
> On May 28, 5:34 am, billshatne..._at_googlemail.com wrote:
>
>
>
>
>
> > I've got to shift our OLTP production database onto a new server which
> > has 8 disks.
>
> > The layout I've got at the moment is the following.
>
> > Please feel free to flame me if you like but I was wondering if I'm
> > being overly cautious with mirroring and should use striping/
> > mirroring.
>
> > Any suggestions for modifications gratefully received.
>
> > 1 + 2 RAID-1
> > OS
>
> > 3 + 4 RAID-1
> > Datafiles
> > Control file
>
> > 5 + 6 RAID-1
> > Archived Redo Logs
> > Control file
>
> > 7 + 8 RAID-1
> > Oracle Software
> > Control file
> > Backups
>
> Well if you have a system with modest IO requirements almost anything
> will work.
>
> You don't give any details about what kind of server or disks or
> operating system or oracle version or if you are going to use ASM
> etc.  No information on what "kind" of backups either.  Does your os
> support asynchronous writes?  Are you planning on using RAW or using a
> cooked file system?
>
> With 8 disks available you are not going to get to get a lot of
> choices or performance.
>
> How about RAID 1 for disks 1/2 and put the OS + oracle software over
> there.
>
> Disks 7/8 for archive logs and backups in RAID 1.  You really don't
> want rman disk based backups writing to the same disks that the
> operating system is on ... that's guaranteed to cripple performance.
>
> That give you a whole 4 disks to work from eh?
>
> For many OLTP systems especially if they are commit happy the IO
> performance of the oracle online logs ( which you appear to have left
> out of your original description ) is critical.  How are you planning
> on meeting those requirements?- Hide quoted text -
>
> - Show quoted text -

I use a 9 "disk" layout on an HP EVA. For you this would mean a minimum of 18 disks.
I suggest you laout your system in a dev environment and do some benchmarking.
As johnb was saying, I don't see you being able to balance I/O with this few disks.

Here is the layout I use on the EVA4400:

Vdisk 1: Oracle Software
Vdisk 2: Oradata 1 (system, sysaux, etc)
Vdisk 3: oradata2 (application data files)
Vdisk 4: archive logs
Vdisk 5: rman backup volume

Vdisk 6-9: online redo logs

Vdisk 2, 3, 6-9 are raid 1 + 0
Vdisk 1, 4, 5 are raid 5 Received on Thu May 28 2009 - 07:58:22 CDT

Original text of this message