Re: RAID and Oracle Databases

Hi,
I This post is not to answer your question, but to point out something to you. You have 5 Hard drives, if you are running RAID1, then there is no reason to have a Hot spare. The Hot Spare will do you no good. If one of your mirrored disks crash, then the data is still available on the other mirrored disk.

If your RAID Box is a 5 drive box,Your best bet is the following: Disk 1,2,3 to be set as RAID5
Disk 4 & 5 to be set as RAID1

This will give you a total of 27GB of data.

If you can add more drives to your RAID Box, then add one more drive. This way you can Run RAID1 on all drives.

Good Luck,
Satar

In article <0ixX1.85$KM4.62743_at_198.235.216.4>,   "mikel" <me_at_here.com> wrote:
> Hi all,
>
> Quick question on RAID controllers and the controller's cache. We just
> purchased a new Dell PE 2300 NT server with a 1X6 hot plugable backplane,
> 5 - 9GB U2 LVD 10K rpm SCSI HDs and Dell's Pert S/C 3 Raid Controller with
> 16 MB cache and no battery backup. We use Oracle NT 7.2 (soon 7.3) mostly
> for our GIS system (40 users), however we are expanding to other apps such
> as Internet/Intranet data retrieval. Most of the work done by the database
> are reads and analysis on data (although I have not collected any real stats
> on this yet).
>
> I originally planned to run the server on a RAID 5 config, however since
> looking into the RAID and Oracle issue a little more, I have decided to go
> with a RAID 1 config with the fifth HD as a hot swap. (I know 45 GB of HD
> for 18 GB of usable HD is costly, however 18 GB will serve our purpose for a
> year or two, so I will examine that issue later).
>
> The RAID controller specs say that because of the no battery backup, the
> controller uses a write though cache only, not a write back cache. I was
> told that any cache was dangerous for an Oracle serve (7.2) and that I
> should disable all caching. My dilemma is should I trust the write though
> cache or play it safe and disable the cache all together and possibly hinder
> the disc I/O performance.
>
> Any comments welcome.
>
> Thanks,
>
> Mikel
>
> >One other point: beware of controllers with spectactular performance - it's
> >usually down to very large on-board cache, which isn't normally battery
> >backed. Lose a controller and you may lose your db. Enable write-thru if
 you
> >aren't sure of how solid the cache protection is.
> >
> >MotoX.
> >
> >
> >>
> >>Any advice you can send my way is VERY much appreciated. Please respond
> >>to all.
> >>
> >
> >
>
>

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