Re: Raid 5 vs mirroring

We went from SSA RAID5 to SSA RAID5 with fast write cache with the following import results:

Import 2.7 million rows
3 indexes inplace
space pre-allocated(used truncate table reuse storage)

SSA RAID5 w/o fast write cache(FWC)= 76 minutes SSA RAID5 /FWC = 21 minutes

I don't have a direct comparison of SSA mirroring to SSA RAID5, but  I did setup a tablespace on 2 SCSI drives with the following results:

Import 2.7 million row
no indexes in place
space pre-allocated

SCSI mirrored = 10 min,
SSA RAID5 c/FWC = 5.3 min

In article <350756B1.DFFBE0_at_writeme.com>,   George Faison <gsf_at_writeme.com> wrote:
>
> Jim,
>
> I can tell you that I implemented a RAID level 5 based solution on the IBM
> RS/6000 platform with excellent results. You would need 5 disks minimum for
> this. You will hear lots of back and forth on the performance, but our
> performance was excellent and we had hot-swappable disks with automatic
> rebuild, etc. so any down-time would be minimal (we never had any due to the
> high-reliability of the IBM disks in the couple of years I was there). I
> would think the other major platforms would give similar results for the most
> part. You can't go wrong w/mirrored disks, but RAID is cheaper and I think a
> very reasonable choice, especially given the reliability of today's disks and
> servers.
>
> Good luck!
>
> George Faison
>
> Jim Chivas wrote:
>
> > Greetings: Does anyone have an opinion on the pros and cons with using
> > raid 5 vs mirroring Oracle databases. We are about to purchase more disks
> > and now have the option. The number of disks were are currently looking at
> > is a 4 disk configuration. WIth mirroring this will mean we need to
> > purchase 8 disks.
> >
> > Performance is an issue as always. The amount of down time in a failure is
> > also a concern.
> >
> > any comments are welcome.
> >
> > Thanks.
> >
> > --
>
>

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