Files and Filegroups
Within a database, data is stored in one or more data files. These files are grouped into logical containers called filegroups. Every database also has at least one log file. Log files sit outside of filegroup containers and do not follow the same rules as data files. This chapter begins by discussing filegroup strategies that database administrators (DBAs) can adopt before it looks at how DBAs can maintain data and log files.
Before considering which filegroup strategies to adopt, it is important that you understand how SQL Server stores data. The diagram in Figure 5-1 illustrates the storage hierarchy ...