Moving Site Collections between Content Databases:Msdn comments: You can move site collections between content databases by using the Stsadm command - line tool or Windows PowerShell 2. 0 commands. There is no graphical user interface for this task [http://technet. microsoft. com/en - us/library/cc825328. aspx ]

Rules:

. The source content database and destination content database must be located on the same instance of SQL Server.
. The source content database and destination content database must be attached to the same Web application.

If you have a content database that is getting too big, you can move one of more of its site collections to a different content database. Run the STSADM - o enumsites command described above and redirect the output to a file; e. g. : STSADM. EXE - o enumsites - url http://Mywebapp:1010 > sites. xmlEdit the output file using Notepad and delete the sites that you do not want to move; i. e. edit the sites. xml file so that it contains the list of site collections in a single content database that you want to move to another content database. You can then use a command like the following to move the site collections to another content database:

STSADM. EXE - o mergecontentdbs - url http:// Mywebapp:1010 - sourcedatabase <databasename> - destinationdatabase <databasename> - operation 3 - filename sites. xml   _{Your Comment}