About recovery considerations for SQL Server files and filegroups
Always have backups of a full set of files and filegroups that constitute the entire database. You also need transaction log backups that span the entire period of time over which the backups were taken. When you have both types of backups, it ensures that you can successfully restore a database from file and filegroup backups. To maintain an unbroken sequence of transaction log backups, it is essential to perform a transaction log backup following every file backup or filegroup backup. If you back up several files or filegroups immediately, then you only need to back up the transaction log after the last such backup. If the transaction log is not backed up, SQL Server does not let you restore a file or filegroup.
SQL Server does not keep a record in the transaction log of new files or filegroups that are created. Therefore, after you add either a file or a filegroup to the database, you must immediately back it up. Then perform a backup of all the filegroups in the database so NetBackup selects the correct recovery set when subsequent backups are performed. Similarly, after you create a database file, you should back up all of the files in the filegroup to which it belongs.