Re: RE: Database Instance

i believe tom kyte recommends putting them in one or a few instances and using VPD to handle security. He claims it scales better. I believe its in his second book and on his website.

However, Thomas is right. You really dont want 13 instances together for maintenance reasons. Some may need different parameter settings.

Are you sure your server can handle all those instances? That could be alot of work for one server. I know the trend these days(and we do it) is get 1 powerful server and load it with instances to save on oracle's obscene licensing fees.

Best thing to do is possibly analyze how the instances are used and combine them into groups of instances.

Your manager sounds like an idiot. What he should do is the following.

Manager: 'DBA, what are the pros and cons of putting all instances into one database? Please research and get back to me. Also, if we decide to combine them, please write up testing scenarios so we can adequately test this approach before implementing it.'

Then he makes a decision. No patience for know it all managers. They cause so many problems.
>
> From: Thomas Day <tday6_at_csc.com>
> Date: 2003/12/26 Fri AM 08:44:25 EST
> To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
> Subject: RE: Database Instance
>
>
> We have 13 databases (and instances) of approximately 17G each on a
> RISC/6000. We have 6 database/instances on a Win2K box. Two of those are
> in the 17G range but the rest are smaller. But it's not the disk size
> that's important, it's the SGA size.
>
>
>
>
> Kean Jacinta
> <jacintakean To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
> @yahoo.com> cc:
> Sent by: Subject: RE: Database Instance
> ml-errors
>
>
> 12/26/2003 01:59
> AM
> Please respond
> to ORACLE-L
>
>
>
>
>
>
> Dear :All
>
> Well we did not buy any application packages.
> Currently we are using open source product ...which
> is Apache and Tomcat.
>
> By the way, have anyone ever have more than 5 database
> under a single server ? I heard that the best practice
> is to have 1 database n 1 application in a single
> server. Is that true ?
>
> Thank
> JKean
>
> --- "Mercadante, Thomas F"
> <thomas.mercadante_at_labor.state.ny.us> wrote:
> > I would be very careful about doing this if you have
> > purchased application
> > packages. Sooner or later, you will want to upgrade
> > one of the packages,
> > and it will require a different release of Oracle -
> > and you will be stuck.
> >
> >
> > Tom Mercadante
> > Oracle Certified Professional
> >
> > -----Original Message-----
> > Sent: Wednesday, December 24, 2003 11:24 AM
> > To: Multiple recipients of list ORACLE-L
> >
> >
> > One other disadvantage of putting all instances
> > together is if you need to
> > say bounce the database (for parameter change or
> > other maintenance etc)
> > then all other applications will get affected.
> > Whereas with separate
> > instances other applications will not get affected.
> >
> > To some extent one application failing will not
> > affect other applications.
> > Except if one application does not close its
> > connections then it could lead
> > to maximum connections (sessions) being reached and
> > affecting other
> > applications.
> >
> > If the nature of the applications is different :
> > OLTP, warehousing then you
> > cannot really tune the parameters.
> >
> > On the positive side I think putting instances
> > together will lead to some
> > memory savings.
> >
> > I would suggest : Do not worry about who wants to
> > put the instances together
> > just list the advantages, disadvantages and make the
> > decision.
> >
> > Stephen.Lee_at_DTAG.Com wrote:
> >
> >
> > It is not necessarily true that an error in one
> > application will affect all
> > applications. If there is a problem with oracle
> > instance or the database,
> > then all applications might be affected.
> >
> > Multiple schemas which have the same table names can
> > be a problem. If your
> > applications uses public synonyms, then you might
> > have a big problem.
> >
> > If everything is working fine now, it seems
> > pointless to move things around.
> > But this is philosophy. I do believe that isolating
> > applications from each
> > other as much as possible is usually a good thing.
> > "Good fences make good neighbors." (usually)
> >
> > But, if your manager insists on it, you have no
> > choice. Just do your best
> > to keep the old stuff around in case it becomes
> > apparent that the new way
> > will not work and you must go back to the old way.
> >
> > > -----Original Message-----
> > > Lately, m! y manager want me to remove all the
> > databases
> > > and remain a single instance. I was wondering if i
> > > move everything into single database then if one
> > of
> > > the application fail due to oracle error , then
> > all
> > > other four application will fail also rite ?
> > >
> > > Each of our web application needs to have 2 schema
> > and
> > > both schema have to be transparent to each other.
> > > While other application schema will be invisible
> > to
> > > each other. Since i have 5 web app then i will
> > need 10
> > > schema.One major problem is all the 10 schema will
> > > contain same table name. It will be a mess putting
> > so
> > > much app in a single db .
> > >
> > > Pls correct me if i am wrong and do let me know
> > what
> > > are the pro and cons or maybe you can educate me
> > with
> > > some of the best practice to setup a proper
> > production
> > > server environment.
> > >
> > > Thank You
> > >
> > > Regards,
> > > Jkean
> > >
> > > >
> > --
> > Please see the official ORACLE-L FAQ:
> > http://www.orafaq.net
> > --
> > Author:
> > INET: Stephen.Lee_at_DTAG.Com
> >
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