Re: Are you good on Performance, Raid and configuration

On Mar 15, 7:36 pm, DA Morgan <damor..._at_psoug.org> wrote:
> Sam wrote:
> > Hi everybody,
> > I need your opinion for a few basic performance and configuration questions,
> > I have a database with a mix amount of read and write and I have a new
> > computer that support Raid with SCSI hard disk,
> > the environment is a development/test environment and redundancy is not
> > important right now,(Just performance is important right now)
>
> > I just have 2 hard disk available right now, which one give me better
> > performance:
> > 1. Mirroring
> > 2. No Mirror and install OS on first hard disk and Oracle on second hard
> > disk
>
> > Second questions , How do you place different oracle files: Data Files,
> > Index Files, Log Files?
> > For example if you select number 2 (No Mirror) on witch hard disk you put
> > Data files, index files and so on to get a better performance?
>
> > Thanks you in advance - Sam
>
> If all you want is speed and you don't care about redundancy then stripe
> both disks and let it go where-ever it is going to go.
>
> My suspicion is that the improvement will be close to unmeasurable but
> given only two disks that is about all you can do.
> --
> Daniel A. Morgan
> University of Washington
> damor..._at_x.washington.edu
> (replace x with u to respond)
> Puget Sound Oracle Users Groupwww.psoug.org- Hide quoted text -
>
> - Show quoted text -

I agree with Daniel. A two disk system is not robust. Your only real performance option is to stripe across both to try for even IO and that is the best you can do.

If you require robustness then your choices are put everything on one disk (not good performance wise) and mirror or place the database on one disk and place the backup and archived redo logs on the other along with one set of online redo logs and a control file. Again not good but it the total volume of data is too large for placing everything on one disk it is an option.

Small RAID-5 arrays are pretty cheap and with a little memory the cache can mask the RAID-5 write penalty for moderate write loads while the use of multiple spindles for distributing the IO can do wonders compared to a couple of non-stripped disks.

HTH -- Mark D Powell -- Received on Fri Mar 16 2007 - 09:04:56 CDT