Re: cache settings NT

That's why you use write cache only if it's "battery supported". Then it should be safe.

Igor Neyman, OCP DBA
ineyman_at_perceptron.com

• Original Message ----- To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com> Sent: Friday, September 06, 2002 2:28 PM

>
> I'll take a shot at this.
>
> Don't have any write caching. Oracle may think that it has safely
> committed the transactions and they are written to disk when they are in
> fact only in cache. If the machine were to shut down ungracefully, i.e.,
> someone kicks out the plug, then your database would not be in a
consistent
> state. Granted, the odds are small, but is it worth the risk? If the
> database is archived and you don't mind the increased chance of having to
> do a recovery then I would say 0% read - 100% write. Oracle is doing it's
> own read caching in the SGA and it's unlikely that the disk cache will
> correctly anticipate Oracle's read requirements. Therefore, caching on
the
> read side is only likely to increase IO. Write caching does not lead to
> any increased IO but it does have some small risk of producing an
> inconsistent database.
>
>
>
> GKor
> @rdw.nl To: Multiple recipients of
list ORACLE-L <ORACLE-L_at_fatcity.com>
> Sent by: root cc:
> Subject: cache settings NT
>
> 09/06/2002
> 04:18 AM
> Please
> respond to
> ORACLE-L
>
>
>
>
>
>
> Hi all
>
> I have the following question for you :
>
> what are the preferred values for the several cache settings on the
fysical
> disk units (NT W2K)
>
> e.g. 100 % read cache - 0 % write cache
> 50% read cache - 50% write cache
>
> is there a difference between settings for an OLTP or DSS solution.
>
> etc
>
> anyone with an explanation
>
> vr. gr.
> g.g. kor
> rdw ict groningen
>
>
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> INET: GKor_at_rdw.nl
>
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-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.com
-- 
Author: Igor Neyman
  INET: ineyman_at_perceptron.com

Fat City Network Services    -- (858) 538-5051  FAX: (858) 538-5051
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