Recently, I heard about a couple of developers that were using the stored procedure SP_SpaceUsed to monitor available disk space.  They had requested additional disk space because the utility had told them that there was only 4mb of unallocated space.  Try not to laugh because these could be YOUR developers.

Last month I blogged about using the procedure to show you the estimated backup size for the database.  But these developers were confusing unallocated space, which is actually just space in the database that has not been allocated.  For example, when you set a autogrowth interval and your database grows in accordance with the interval you will now have unallocated space until the database takes that free space.  Enjoy!