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

"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 - 02:45:16 CDT