RAID 1 vs RAID 0/1

[Axel Schneider]

[email]ucstyle@hotmail.com[/email] (Ken) wrote in message news:<d526473a.0306260607.7a0c3c49@posting.google. com>...

> [email]ucstyle@hotmail.com[/email] (Ken) wrote in message news:<d526473a.0306160838.74d71dca@posting.google. com>...

> > Thanks,
> >
> > The idea with doing RAID 1 on the servers was to eliminate having a
> > RAID 0/1 and having difficulty with adding disk, etc. We're thinking
> > RAID 1 will make maintenance a little and have Oracle handle how it
> > writes data to the disk.
> >
> > Has this practice been used and has has it functioned (hot disk, high
> > I/O, etc)
> >
> > THanks
> >
> > "Gerd Walther" <gerd.walther@t-online.de> wrote in message news:<bchihr$35t$01$1@news.t-online.com>...

> > > Hallo,
> > >
> > > Oracle cannot stripe for the system.
> > > Oracle striping is only a distribution of datablocks on several disks but no
> > > striping.
> > > At first you must create more then one datafile on difference disks. Then
> > > the
> > > min extent storage clause must defined as 2. Then Oracle writes at first
> > > one datablock
> > > in the first extent in the first datafile on the first drive and then in the
> > > other extent in ......
> > > So you can minimize hot spots , but it is not real striping.
> > >
> > > Better for performace ist real striping with AIX and the mirroring but it
> > > isn't cheaper.
> > >
> > > Best regards
> > >
> > > Gerd
> > >
> > > "Ken" <ucstyle@hotmail.com> schrieb im Newsbeitrag
> > > news:d526473a.0306120858.5254cfb2@posting.google.c om...
> > > > AIXers,
> > > >
> > > > Has anyone out here have a system configuration where Oracle handles
> > > > the striping across the drives while the system just handles Mirroring
> > > > across the drives??
> > > >
> > > > I'm working with the DBA and he's wanting to have Oracle do the
> > > > striping and the system just does the mirroring?? If so, does anyone
> > > > have any feedback on this??

>
> THANKS,
> So have you ever ran oracle on a system that's RAID 1? do you have any
> system performance stats? We're looking at this, understand that it's
> not RAID 0 (in the AIX sence), is there high I/O during sequential
> read/writes??

Hi Ken,

we have a CRM system (SAP) running on a Oracle DB.(A huge amount of
I/O)
The system was running with RAID 1 (LVM Mirror) for about a year and
we always had problems with Disk I/O.
3 Month ago we changed the Oracle Datafiles to RAID 10. All LV's
striped over 10 Disks and mirrored to 10 other disks (all SSA Disks).
We have improved our Disk I/O enormously. (Avrg I/O time from 100-200
ms to 10-20 ms).

regards
Axel

[Ken]

[email]axelsche@gmx.de[/email] (Axel Schneider) wrote in message news:<c70d3212.0306262336.46dd300e@posting.google. com>...

> [email]ucstyle@hotmail.com[/email] (Ken) wrote in message news:<d526473a.0306260607.7a0c3c49@posting.google. com>...

> > [email]ucstyle@hotmail.com[/email] (Ken) wrote in message news:<d526473a.0306160838.74d71dca@posting.google. com>...

> > > Thanks,
> > >
> > > The idea with doing RAID 1 on the servers was to eliminate having a
> > > RAID 0/1 and having difficulty with adding disk, etc. We're thinking
> > > RAID 1 will make maintenance a little and have Oracle handle how it
> > > writes data to the disk.
> > >
> > > Has this practice been used and has has it functioned (hot disk, high
> > > I/O, etc)
> > >
> > > THanks
> > >
> > > "Gerd Walther" <gerd.walther@t-online.de> wrote in message news:<bchihr$35t$01$1@news.t-online.com>...
> > > > Hallo,
> > > >
> > > > Oracle cannot stripe for the system.
> > > > Oracle striping is only a distribution of datablocks on several disks but no
> > > > striping.
> > > > At first you must create more then one datafile on difference disks. Then
> > > > the
> > > > min extent storage clause must defined as 2. Then Oracle writes at first
> > > > one datablock
> > > > in the first extent in the first datafile on the first drive and then in the
> > > > other extent in ......
> > > > So you can minimize hot spots , but it is not real striping.
> > > >
> > > > Better for performace ist real striping with AIX and the mirroring but it
> > > > isn't cheaper.
> > > >
> > > > Best regards
> > > >
> > > > Gerd
> > > >
> > > > "Ken" <ucstyle@hotmail.com> schrieb im Newsbeitrag
> > > > news:d526473a.0306120858.5254cfb2@posting.google.c om...
> > > > > AIXers,
> > > > >
> > > > > Has anyone out here have a system configuration where Oracle handles
> > > > > the striping across the drives while the system just handles Mirroring
> > > > > across the drives??
> > > > >
> > > > > I'm working with the DBA and he's wanting to have Oracle do the
> > > > > striping and the system just does the mirroring?? If so, does anyone
> > > > > have any feedback on this??

> >
> > THANKS,
> > So have you ever ran oracle on a system that's RAID 1? do you have any
> > system performance stats? We're looking at this, understand that it's
> > not RAID 0 (in the AIX sence), is there high I/O during sequential
> > read/writes??

>
> Hi Ken,
>
> we have a CRM system (SAP) running on a Oracle DB.(A huge amount of
> I/O)
> The system was running with RAID 1 (LVM Mirror) for about a year and
> we always had problems with Disk I/O.
> 3 Month ago we changed the Oracle Datafiles to RAID 10. All LV's
> striped over 10 Disks and mirrored to 10 other disks (all SSA Disks).
> We have improved our Disk I/O enormously. (Avrg I/O time from 100-200
> ms to 10-20 ms).
>
> regards
> Axel

Thanks Axel,

Were you running Oracle using Oracle in a pseudo striping capacity?
I've never seen this configuration but my DBA is bent that it (Oracle)
can handle the placement of the datafiles across multiple disk and in
essence have some form of striping. We have a RAID 0/1 on 6 drives now
that we use for data files. Do you remember the numbers with your high
I/O on average??

thanks