Microsoft® SQL Server 2012 Unleashed

Database Filegroups and Performance

Filegroups allow you to decide where on disk a particular object should be placed. You can do this by defining a filegroup within a database, extending the database onto a different drive or set of drives, and then placing a database object on the new filegroup.

Every database, by default, has a primary filegroup that contains the primary data file. There can be only one primary filegroup. This primary filegroup contains all the pages assigned to system tables. It also contains any additional database files created without specifying a filegroup. Initially, the primary filegroup is also the default file group. There can be only one default filegroup, and indexes and tables that are created without specifying ...