Using Multiple Instances

Although running multiple instances of Microsoft® SQL Server™ 2000 on a single computer expands the capabilities of SQL Server, the recommended configuration for most production databases servers is to use a single instance of SQL Server with multiple databases.

Using a single instance of SQL Server on a production server offers these benefits:

• Only one instance needs to be administered.
  
  
• There is no duplication of components or processing overhead, such as having to run multiple database engines on the same computer. This means that the overall performance of a server with a single instance may be higher than a server running multiple instances.
  
  
• A single instance of SQL Server 2000 is capable of handling the processing growth requirements of the largest Web sites and enterprise data-processing systems, especially when it is part of a federation of database servers. For more information, see Federated SQL Server 2000 Database Servers.

Running multiple instances of SQL Server on a single computer is best:

• When you must support different systems that have to be securely isolated from each other, such as when a service bureau has a large server and must create a separate instance of SQL Server for each customer.
  
  
• When you need to support multiple test and development databases, and the most economical configuration is to run these as separate instances of SQL Server on a single large server.
  
  
• When you need to run multiple applications on a desktop, and each application installs a separate instance of SQL Server 2000 Desktop Engine.