Re: 30 instances on one host

Daniel Morgan wrote:
>
> Sean M wrote:
>
> > I could be misinterpreting Daniel, but I think he's still talking about
> > a 1-to-1 relationship between instance and database, but that he's only
> > running a subset of his databases at one time. So the host has, say, 6
> > databases on it, but only 3 of which are actualy instantiated at any
> > given point (the others are just shutdown, not consuming any resources
> > other than disk space).
> >
> > Regards,
> > Sean M
>
> I've never talked about a 1:1 relationship between databases and instances. The
> CREATE DATABASE command has a parameter for MAX INSTANCES.
>
> I just wasn't sure that, while trying to follow the thread and learn from the
> rest of you, that you were all talking about the same thing. Some seemed to use
> the word instance in the technically correct manner while others were using it
> to mean instance. And no one seemed to notice or care except this poor soul who
> was hanging onto every keystroke.
>
> I've had lots of servers with multiple databases. But multiple instances on one
> machine? A few times but I've never felt good about it.
>
> Daniel Morgan

OK, that's the last time I try to interpret what someone else meant and speak for them. :) So, please, Daniel, what are you talking about? You've now lost me. Strictly speaking, an Oracle instance (as Pete already said) is the sum of SGA and background processes. An Oracle database consists of controlfiles, datafiles, and online redo logs. The true relationship is many instances to one database. But that's only possible if RAC/OPS is involved. Otherwise the relationship is one-to-one, and since relatively few sites run RAC/OPS, the words tend to get used interchangably. I assumed all of us here in this thread understand these definitions and were on the same page, but now I'm not sure... So Daniel, can you please explain what you mean by having multiple databases on one machine but not multiple instances (which implies a many databases to one instance relationship)?

Thanks,
Sean M Received on Thu Jun 20 2002 - 18:49:55 CDT