SQL Server 2008 FILESTREAM

Implementing SQL Server 2008 FILESTREAM functionality
The new FILESTREAM functionality in SQL Server 2008 lets you configure a varbinary(max) column so that the actual data is stored on the file system, rather than within the database. You can still query the column as you would a regular varbinary(max) column even though the data itself is stored externally.

The FILESTREAM feature integrates Windows NTFS with the SQL Server database engine by storing binary large object (BLOB) data as files on the local file system. You can use Transact-SQL statements to query, insert or update the data, or you can use Win32 file system interfaces for direct streaming access to the data.

Microsoft recommends that you use FILESTREAM only if (1) your BLOB data files are, on average, larger than 1 MB, (2) you need fast read access to that data, and (3) your application uses a middle tier for application logic. Otherwise, you should use a regular varbinary(max) column.

If you do decide to implement a FILESTREAM column, you'll need to take the following steps:
Enable FILESTREAM support on the SQL Server 2008 service.
Configure the database to support FILESTREAM storage.
Define a column that supports FILESTREAM storage.