If one database can be accessed by only one instance of SQL Server, how
would you configure SQL Server (and hardware) to work in a large user based
environment? Would you split the database off to two or more servers or
would you use a multi instance setup on a multi processor server?

SQL server is designed to scale UP. That means big multi-processor boxes.
You can have multiple databases that are logically disconnected (no DRI, no
need to synch transactions and backup/restore) to speed up backup and
restore strategy, but that has almost no effect on scalability. You can
have MANY concurrent users into a single database with the correct hardware
and application software.

--
Geoff N. Hiten
Microsoft SQL Server MVP
Senior Database Administrator
Careerbuilder.com

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