This white paper describes the FILESTREAM feature of SQL Server 2008, which allows storage of and efficient access to BLOB data using a combination of SQL Server 2008 and the NTFS file system. It covers choices for BLOB storage, configuring Windows and SQL Server for using FILESTREAM data, considerations for combining FILESTREAM with other features, and implementation details such as partitioning and performance.

This white paper is targeted at architects, IT Pros, and DBAs tasked with evaluating or implementing FILESTREAM. It assumes the reader is familiar with Windows and SQL Server and has at least a rudimentary knowledge of database concepts such as transactions.

In today’s society, data is generated at incredible rates and often needs to be stored and accessed in a controlled and efficient way. There are various technologies to do this and the choice of technology often depends on the nature of the data being stored – structured, semistructured, or unstructured:

• Structured data is data that can be easily stored in a relational schema, such as that representing sales data for a company. This can be stored in a database with a table of information for products the company sells, another with information about customers, and another that details sales of products to customers. The data can be accessed and manipulated using a rich query language such as Transact-SQL.
• Semistructured data is data that conforms to a loose schema but does not lend itself well to being stored in a set of database tables, such as data where each data point could have radically different attributes. Semistructured data is often stored using the xml data type in the Microsoft® SQL Server® database software and accessed using an element-based query language such as XQuery.
• Unstructured data may have no schema at all (such as a piece of encrypted data) or may be a large amount of binary data (many MBs or even GBs) which may seem to have no schema but in reality has a very simple schema inherent to it, such as image files, streaming video, or sound clips. Binary data in this case means data that can have any value, not just those that can be entered at a keyboard. These data values are commonly known as Binary Large Objects, or more simply BLOBs.

This white paper describes the FILESTREAM feature of SQL Server 2008, which allows storage of and efficient access to BLOB data using a combination of SQL Server 2008 and the NTFS file system. It covers the FILESTREAM feature itself, choices for BLOB storage, configuring the Windows® operating system and SQL Server for using FILESTREAM data, considerations for combining FILESTREAM with other features, and implementation details such as partitioning and performance.

http://msdn.microsoft.com/en-us/library/cc949109(v=sql.100).aspx