Re: Upgrade to big SUN box or RAC for data warehouse?

This type of I/O waits *can* slow the database down. As always, YMMV. But it can happen.

HTH,
Brian

Ryan Gaffuri wrote:
>
> "Tanel Poder" <tanel@@peldik.com> wrote in message news:<3f1d9a46$1_1_at_news.estpak.ee>...
> > Hi!
> >
> > No, 2 phase commit is used in transactions distributed between different
> > databases.
> > RAC doesn't increase IO per se, but it allows to overcome CPU (and memory)
> > bottleneck, thus allowing more IO to be done. But since you still operate
> > with the same number of disks, they can't service any more IO requests. A
> > disk with average 5ms seek time can service 20 IO requests per second, but
> > if you got more and more requests coming, they will queue up and the queues
> > will grow until you start having problems such are IO timeouts etc..
> >
> > Tanel.
> >
> > "Ryan" <rgaffuri_at_cox.net> wrote in message
> > news:PTfTa.875$5b7.404_at_lakeread01...
> > > why would implementing RAC increase I/O? is that because of the 2 phase
> > > commit? So you have to write to multiple datafiles?
>
> so will this type of increased I/O waits actually slow the database
> down? or will it run at the same performance level?

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