Re: Does RAID 5 contradict and minimize the benefit of OFA on NT?

Answers embedded
david spaisman <david.spaisman_at_compaq.com> wrote in message news:8c2sr8$55r$1_at_mailint03.im.hou.compaq.com...
> Hello:
>
> I am working on Oracle 8.0.5 application on NT 4.0. We are in the process
of
> setting up a user acceptance server and a development server and have the
> luxury of having as many disk servers as needed on each respective
> server(within reason).
>
> I am thinking of going with a configuration of drives consisting of the
> following:
>
> a) Oracle executibles, redo log group members, control file, system
> tablespace
> b) data files, user files, control file, redo log members
> c) index files, control file, redo log members
> d) rollback segments, export files, backup files
> e) archive log files.
>
> Hopefully this configuration will be with physically separate drives and
> more than one controller If these are logically partitioned drives, I
> believe it will still depend on how many physical drives and controllers
> are involved. THanks.
>
> David Spaisman
>
>
> However, I have been told that RAID 5 will reduce or contradict the
> ebenfits purportedly gained from the multiple disk drive/OFA
configuration.
>
> 1) Has any one found this to be true?
>

Yes, basically you really can't distribute your data as all your logical volumes are spread out on several physical volumes. If you dedicate 1 RAID disk to indexes, your indexes will still show everywhere.

> 2) Will the benefit of RAID 5 -- faster reads versus slower writes -- for
a
> transactonal database still apply?
>

No, RAID 5 will hurt performance and cause bottlenecks especially for files being sequentially written only, like redo log files. Your setup with redolog files on disks with tablespaces is likely to result in performance hits.
> 3) Has any one seen Oracle position on the value OFA versus the benefit
of
> RAID 5?
>

No, though the consensus in this group is : use a combination of RAID0+1 and RAID-5, do NOT place critical files on RAID-5 devices. A recent article in the Dutch Oracle Magazine Optimize summarizes as follows.
If your database has less than 50 users and/or less than 250 OLTP transactions per minute there should be no objection against RAID5. If one of these parameters is exceeded and/or you are running more databases on one server, you should consider using other disks. The article discusses heavy OLTP environments, I'm not sure whether you need that, and it will be a hell of a lot of work to translate from Dutch to English.

Hth,

Sybrand Bakker, Oracle DBA

> 4) Any other information concerning this situation will be greatly
> appreciated.
>
> Thanks.
>
> David Spaisman
>
>
>
>
Received on Fri Mar 31 2000 - 13:32:20 CST