Re: performance/scalability and multiple instances

"Ron Bergeron" <bergeror_at_asitshouldbe.com> wrote in message news:Pine.LNX.4.44.0301271500190.7387-100000_at_machine.asitshouldbe.com...
> I am working with someone who has 12 Oracle instances running on a single
> Sun server. Each of these instances is a data warehouse with anywhere from
> 50-500 GB of data in it. Each DW is completely unrelated to the others.
>
> They have performance and scalability concerns. My recommendation to them
> is to split the instances up and put them on separate boxes. They can't
> buy one server per instance, but at least they could split the 12
> instances up over three or four machines.
>
> If they do spread the instances over multiple servers, all servers would
> share a high-end disk array (Hitachi 9970).
>
> My questions are:
>
> 1) Is putting 12 heavy duty, large DW instances on a single box a Bad Idea
> for performance? It is obviously a Bad Idea from an "all your eggs in one
> basket" perspective.
>
> 2) Is there a white paper or something similar that supports my opinion
> that scaling unrelated instances horizontally is more scalable than
> scaling vertically?
>
> 3) Other than CPUs, memory, and I/O, are there any other resources that
> multiple instances on one server contend for? (ie: semaphores, locks,
> whatever)
>
> They did voice one opinion that might have some merit. They said that if
> all the instances are running on one large machine, and a few of those
> instances are idle at the time (instantiated, but not processing any
> queries), then the remaining databases can take advantage of the unused
> CPU cycles from the idle instances.
>
> Thanks for any input you might have.
>
> Ron

Presumbly they are paying by the hour for consultancy. How much are you offering?

Regards,
Paul Received on Tue Jan 28 2003 - 14:43:18 CST