A common question for new users of SQL Server is how SQL Server is licensed. There are three options for the Enterprise and Standard editions, and you should choose an option based on your projected usage. The three options are:

Per Processor: This means you would get a license for each processor on the machine where SQL will be running. However, because of the multi-core processor machines that are now available, this is a bit confusing. Microsoft considers each physical processor (sometimes called a socket) as a processor in a multi-core system. So a machine that had two processors would require two licenses; a machine with two dual-core processors would still only require two licenses, as would a machine with two 4-core processors. Web-based applications are almost always licensed per processor as there is not really a way to know or license clients.

Per Device: Although a computer is considered a device, this option is targeted for scenarios where what we usually think of as devices are used to connect to SQL Server; i.e. phones, kiosks. These are usually non-web applications.

Per Client Access License (CAL): This option is similar to the per device option, but is targeted at the scenario where one user may have multiple devices that need to connect. Again, this would seldom be a web-based application.

Complete information on licensing of SQL Server 2005 can be found here. The whitepaper on licensing also goes into depth around complex scenarios such as with clustering, mirroring, replication, etc.

sharon bjeletich | SQL Server Program Manager

This blog is provided by Sharon Bjeletich and does not reflect the views, opinion, or advice of Microsoft Corporation.