Re: Archive Log Creation Rate??

"Richard Foote" <richard.foote_at_bigpond.com> wrote in message news:<gmVeb.133690$bo1.108644_at_news-server.bigpond.net.au>...
> "Charles Davis" <cdavis10717_at_comcast.net> wrote in message
> news:a-GdnTG0_8tG0eaiU-KYuA_at_comcast.com...
> > Hi, all.
> >
> > I am looking for opinions about sizing ReDo logs vs the rate at which
> > Archive Logs are created.
> >
> > Oracle suggests archiving once every 20-30 minutes.
> >
> > Others suggest archiving more frequently to minimize potential data loss
> and
> > for a shorter recovery/warm start when reading the most recent archive
> log.
> >
> > Either approach affects the ReDo sizes specified for the average database
> > taking into account the usual logged update activity.
> >
> > I was cutting a 200MB archive log every 5 minutes, then I increased ReDo
> to
> > 1GB to archive less frequently, more in line with what Oracle suggested.
> >
> > What's your opinion or experience? I'd love to hear it.
> >
>
> Hi Charles,
>
> One thing I would suggest is to read up and research how Oracle now
> implements incremental checkpointing (since 8i). It kinda negates many of
> the arguments regarding how one should size redo logs with regard to both
> instance recoveries and checkpointing issues. I remember discussing all this
> a while ago so a quick search on google should provide some information.
>
> The key parameters for this are fast_start_io_target (8i) and
> fast_start_mttr_target (9i).
>
> Cheers
>
> Richard

careful, some of those features are Enterprise Edition, only. At least, that's what the alert log tells me, which I tend to trust more than the docs :D

Pd Received on Fri Oct 03 2003 - 11:56:07 CDT