Re: Databases and Instances

Stefan Jahnke wrote:
>
> Hi,
>
> I wonder wether it is possible to create one instances, but multiple
> databases that are accessed via the one instance (on the same server)
> like it is possible to do with DB2. As I understood, you make an entry
> in the oratab-file to have a new instance, then connect with svrmgrl as
> internal to that instance, start it (what actually means, there is a
> seperated bunch of oracle processes per instance with an SGA). But there
> is only one DB that can be mounted and opened per instance. The only
> thing I found is the parrallel server option, but this is the other way
> around: multiple instances accessing the same database. So, is it
> possible to have one instance accessing mounting and opening multiple
> databases ? Perhaps via init-file entries ? I don't want just database
> links.
>
> TIA
> Stefan

So, after all the replies, I think it's just different concepts. It may work pretty well to have several schemas in one Oracle Database to logically seperate data for several applications etc. The only disadvantage I see here is, that you only have one SGA and it might be problematically to tune one instance for different demands. After all, the thing to do would be: Build seperate instances or, at least for production, even put completely seperated installations on physically seperated machines. Of course, you encounter the same problem when you have 2 or more databases within one DB2 instance. Actually, I think it's funny how people start throwing mud at each other when it comes up to "what database is the best......". I personally think, at least Oracle and IBM are both pretty well. It doesn't really make a difference wether several of the features are different. By the way, does somebody really have a proof on how good or bad informix, sybase (or sql server, but that's the same code-base anyway :-) or others compare to oracle or db2 when it comes to things like perfomance, scalability and how stable are they ?

Bye
Stefan Received on Fri Mar 31 2000 - 00:00:00 CST