Re: Obvious problems

Separate index segments (indexes) from data segments (tables). Place on different Disks.
1 rollback segment for every 10 users.
Make sure you have the appropriate tablespaces for your environment. Check init file for appropriate memory allocation for your environment. Read the Concepts guide to get a better understanding of how Oracle works.
Understand what the DB is going to be used for. Make a backup plan based on business needs. Good luck.

Bill

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William Dangren
Navis Enterprises
407.348.6401
800.219.0207