Re: VLDB Redo Log Sizing Suggestions

Brian Peasland wrote:
>
> Personally, I don't feel that archiving every 5 to 8 minutes is
> excessive during high volume periods. Keep in mind that if you increase
> your online redo logs, that during your low volume periods, you may only
> switch every few hours. In other words, taking action to "correct" one
> thing can have an effect on another thing.
>
> HTH,
> Brian
>
> Charles Davis wrote:
> >
> > Hi, all,
> >
> > I am looking for some expert guidance on re-sizing my SAP R/3 database re-do
> > logs.
> >
> > I have 8 groups of mirrored logs, each log file is 200MB.
> >
> > I am archiving a log file every 5 to 8 minutes. This seems excessive.
> >
> > Suggestions?
> >
> > Oracle wants me to archive about every 20-30 minutes. Is a re-sizing as
> > simple as tripling or quadrupling the re-do log sizes?
> >
> > Should I learn and use LogMiner to see what's going on and to influence the
> > re-sizing?
> >
> > This is occurring in a 1TB SAP R/3 database, with the application code
> > supplied by SAP, so I have little change to knowing or altering the souce
> > code that may be causing excessive logging.
> >
> > I deeply appreciate any suggestions on this topic.
> >
> > Many Thanks, and Happy July 4th (USA Independence Day!!)
> >
> > Charles
>
> --
> ===================================================================
>
> Brian Peasland
> oracle_dba_at_remove_spam.peasland.com
>
> Remove the "remove_spam." from the email address to email me.
>
> "I can give it to you cheap, quick, and good. Now pick two out of
> the three"

An alternative to this is to use either:

1. archive_lag_target on v9,
2. have massive log files and control the switching with dbms_job at regular intervals..

then you get the best of both worlds

-- 
=========================
Connor McDonald
http://www.oracledba.co.uk

"Some days you're the pigeon, some days you're the statue"