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

Hi!

If you want to get your load dimes down with RAC you have to separate the loading processes the way that they aren't doing write activity to same datablocks. In DW environment, it shouldn't be hard, because usually the fact tables are only inserted anyway and you can have own set of intermediate processing tables for each node.

But if you got 8 RAC nodes, each having it's own gigabit connection to NAS box, the NAS box might remain bottleneck. You just have to find out what is it's capacity.

Tanel.

"Larry" <larry07_at_imap.cc> wrote in message news:93e49a46.0307222345.4bbf6997_at_posting.google.com...
> "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..
> >
>
> That is one of our fears. The vendor has told us the 12K will fix all
> our problems but will it reduce the 90 hour load times to something
> that can be done in a day? I have since learned that the CPU is
> pretty busy doing load so the bottleneck could be CPU but we haven't
> done the work to find out if the IO channels are completely full
> either. I have been told the 12K has much better IO so it can take
> advantage of the GBE NAS and it has two NIC's so we can do twice the
> IO's(?) so maybe with faster processing of the input tapes and better
> IO to the NAS, we can achieve the SLA's we want?
>
> Larry
> > 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?
Received on Wed Jul 23 2003 - 08:03:16 CDT