The Art of SQL Server FILESTREAM - Red Gate Software

Chapter 10: Integrating FILESTREAM with other SQL Server FeaturesFILESTREAM and ReplicationReplication technologies provide a means to copy data from a primary database(publisher) to one or more secondary databases (subscribers). Even though replicationwasn't designed for all the functions DBAs use it for today, it is nevertheless widely usedas a solution for reporting, load balancing, synchronization, high availability, disasterrecovery, and so on. SQL Server supports replicating FILESTREAM data but, of course,FILESTREAM data is stored outside the database (in the file system) and is often used tostore very large data files, so it is interesting to examine how replication of FILESTREAMenableddatabases works.Replicating FILESTREAM columnsWhen replicating SQL Server 2008 FILESTREAM-enabled databases, FILESTREAMcolumns can be replicated either with or without the FILESTREAM attribute.If you replicate FILESTREAM columns with the FILESTREAM attribute, FILESTREAMdata values on the publisher column will go to a FILESTREAM column on the subscriber.When you replicate a FILESTREAM database to a SQL Server 2008 or later instance,in most cases you would want to replicate the FILESTREAM attribute along with theFILESTREAM columns.If you replicate FILESTREAM columns without the FILESTREAM attribute, FILESTREAMdata values on the publisher will be replicated as VARBINARY(MAX) columns on thesubscriber. In this way, it's possible to replicate a table with FILESTREAM columns to aSQL Server 2005 subscriber, which doesn't support FILESTREAM. However, it is notpossible to replicate FILESTREAM columns to SQL Server 2000 subscribers. Table 10-1summarizes the FILESTREAM replication support with previous versions of SQL Server.352