Microsoft® SQL Server 2012 Unleashed

Secondary Files

You can create zero or more secondary data files in a database. These files, by default, are identified with the .ndf extension, but the extension can be different. Secondary data files provide an opportunity to spread the data that SQL Server stores over more than one physical file. This capability can be particularly useful for larger databases and can help with performance and management of database files. Consider, for example, a situation in which a database server has four physical drives available for the data file(s). Each drive is 1GB in size, but the database you are creating is 2GB. In this example, the database will not fit on one drive. A solution to this problem is to create a primary data file on one of the drives ...