Re: Raid quiz

Hi,

    About Raid5 and Raid10, is it right: Ordinary disks: (0.8 + 1*0.2)(1000 IOPS)/(75 IOPS/disk) = 13.3 Mirrored disks: (0.8 + 2*0.2)(1000 IOPS)/(75 IOPS/disk) = 16 Raid 5 disks: (0.8 + 4*0.2)(1000 IOPS)/(75 IOPS/disk) = 21.3
>From link http://www.aixtips.com/AIXtip/sizing_disk_for_io.htm

    I am wondering whether all raid1 read policy are round robin, that is ,N disk raid1 can do N* 75 IOPS, or It can only do N/2 * 75 IOPS?

Regards
zhu chao
msn:chao_ping_at_163.com
www.cnoug.org
----- Original Message -----
To: "LazyDBA.com Discussion" <oracledba_at_lazydba.com> Sent: Saturday, May 10, 2003 5:58 AM

> I assume the 6 drives are identical. RAID 1+0 or 0+1 will give you the
> best performance, but you will get use of only 3 drives -- the other 3 are
> pure mirroring. RAID 5 will be slower for writes, but you will get use of
4
> of the drives, I believe. RAID 1+0 and 0+1 are very similar, but RAID
1+0
> is easier to handle in a disaster recovery scenario. Jonathan Lewis has
> good material on this in his book "Practical Oracle 8i". I went with
RAID
> 1+0. Diskspace is cheap these days.
>
>
>
> >From: "Chawhan, Samee" <Samee.Chawhan_at_capmetro.org>
> >To: "LazyDBA.com Discussion" <oracledba_at_lazydba.com>
> >Subject: RE: Raid quiz
> >Date: Fri, 9 May 2003 14:50:21 -0500
> >
> >Ok all you DBA gurus,
> >
> >Interesting real life question:
> >
> >We have a NT server we will use for several small 9i databases and daily
> >two
> >online hot backups.
> >
> >We have 6 drives.
> >
> >Space is not an issue right now. In other words the databases are very
> >small
> >and backups are small too.
> >
> >How would you setup the drives...raid 5, raid 0+1, raid 1+0 or no raid
for
> >backup drives.
> >
> >Samee
> >
> >
> >
>
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