Microsoft® SQL Server 2008 R2 Unleashed

Using Filegroups

All databases have a primary filegroup that contains the primary data file. There can be only one primary filegroup. If you don’t create any other filegroups or change the default filegroup to a filegroup other than the primary filegroup, all files will be in the primary file group unless specifically placed in another filegroup.

In addition to the primary filegroup, you can add one or more filegroups to the database, and a filegroup can contain one or more files. The main purpose of using filegroups is to provide more control over the placement of files and data on your server. When you create a table or index, you can map it to a specific filegroup, thus controlling the placement of data. A typical SQL Server database installation ...