Re: 30 instances on one host

Sean M wrote:

> Daniel Morgan wrote:
> >
> > Sean M wrote:
> >
> > > It's not entirely academic - as I said in my other post, there are some
> > > valid justifications for such a configuration (training, support,
> > > etc.). But generally I agree - this sort of architecture is highly
> > > specialized, and almost always used for situations where
> > > performance/robustness/scalability are not the primary concern.
> > >
> > > Regards,
> > > Sean
> >
> > I disagree. I can not believe there is any justification.
> >
> > I challenge anyone to give me a rationale whereby 10 instances makes more sense
> > than 2 or 3.
> >
> > And lets make sure here that we are using the word 'instance' to mean 'instance'
> > and not to mean 'datab ase'. You are talking about 10+ running Oracle
> > executables. 10+ oracle_sids. 10+ * the number of threads in a single instance.
>
> Well, as I said in my other post, a training class for Oracle would be a
> good example. Each student gets his or her own database (actual
> distinct Oracle database) for exercises so as not to conflict with the
> other students in the class (or in the next classroom over, for that
> matter). Each student needs his/her own because the class is on
> backup/recovery, or How to Build an Oracle Database, etc. (any sort of
> DBA-type class where each student needs complete control over his or her
> own database for the hands-on portion). Say 20 students per class, one
> server per class, 20 instances/databases per server. That makes far
> more sense than running 10 servers with 2 databases each for every class
> in terms of cost and managability, which clearly have a higher priority
> in this example than performance, etc. That's not to say performance
> isn't a consideration - you don't want the students waiting around. But
> you also don't want to spend the unjustifiable sums required to give
> each student his own server. Hence, like everything else, a compromise
> between cost/performance/managability must be struck.
>
> Another example might be a support organization. Each telephone analyst
> might need a scratch instance to run simple tests on. You have 60
> analysts. It would not make sense to buy 60 servers to run 60 test
> instances on. You buy 2 or 3 big ones and run 20 or 30 many small
> databases on each. Again, peformance takes a back seat to managability
> and cost, but that's perfectly acceptable and sane - the correct choice
> for this particular example.
>
> But again, these are special cases. In the vast majority of situations,
> 20 or 30 databases on a single host would not be the correct, sane
> choice.
>
> Regards,
> Sean

I agree. But you are changing terminology in midstream to make your point. You are talking databases. The original question related to instances. They are not the same thing.

And I specifically in my posting that you responded to made a point of differentiating in case there was a misuse of terminology.

10+ databases I can understand. 10+ instances? No but I'm open to persuasion if someone can make a good case.

Daniel Morgan Received on Thu Jun 20 2002 - 01:02:08 CDT