Re: Multiple Instances Vs Multiple Servers

The answer to one big server with three Oracle instances or three servers with one instance each depends on what each instance is for. If the applications in one instance will regularly need to access data in one or both of the others then you will be better off combining them into one instance to prevent having to use distributed queries.

On the other hand if one or all of the instance applications are pretty well independent of each other then you will definitely benefit from running a separate instance for each. A separate server for each actually depends on size, load, growth rate, and availability requirements. A small static system dozen user system can sit on the same box, while a heavy hit, rapidily changing, and growing database will be better off separate.

One more thing to consider is if any of the applications you plan on running are purchased packages. Sometimes a vendor package will not run on the next release without work. If you put three canned packages into one instance you can end up having your Oracle upgrades being held back but the weaker vendor while one of the other packages requires upgrading to run the next release.

Parallel server is definitely an option for a large closely related application.

Good Luck.
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Mark Powell -- The only advise that counts is the advise that you follow so follow your own advise Received on Fri Apr 11 1997 - 00:00:00 CDT