Re: RAID Newbie question...

In article <A3C801763DAFD411A57900508B9AAF972941_at_HEARTOFGOLD>,   kfrendo_at_bvb.gi (Kelly-Anne Frendo) wrote:
>
> I think you may be getting the same confusion that I had a few weeks
 back.
> (Check for answers to my question on RAID 5 on this newsgroup - it may
 help
> clarify matters)
>
> I am new to Oracle, but I was clear with the concept of different
 files, etc
> on their own physical disks, e.g. log file members/groups, indexes,
 data,
> etc. Then I was confused because the use of RAID seemed to ignore all
 this
> completely.
>
> The way I see things now, is that if you use RAID5, the
 recommendations for
> different physical disks for different Oracle things go down the drain

• you
  > cannot use both the Oracle best practices and RAID 5 at the same time.
  What
  > I have learnt from this newsgroup is that RAID5 is not a good idea for
  > Oracle databases, so I guess it is best to forget RAID5 for database
  > systems, and instead use the concepts of splitting indexes, logs,
  etc.on
  > different disks as recommended by Oracle.
  >
  > I hope this helps. My answer may be a little fuzzy as I am still
  slowly
  > getting the understanding of this myself.
  >
  > K.
  

K,

it is bad idea to use RAID 5 where sequential writes/write intensive tasks are needed.
E.g. in case of oracle - redo logs. other things like temp tablespace , rbs also do not do well with RAID5.

but theorotically, read inetensive tasks benifit from RAID 5. E.g. if u have database which is 'read only' during the week and data is loaded on weekends, it may see a good performace during the week with RAID 5 for data and indexes.

so u can always use RAID 5 for data and indexes depending on the application but make sure
to put write intensive things like redo, rbs, temp on plain disks with no RAID or if u want security use mirroring but not RAID5.

BTW, what is ur environment ? OS, oracle version ? type of app ? hope this helps,
D

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http://www.deja.com/ Received on Thu Jan 11 2001 - 10:49:35 CST