Indexes (with the exception of the clustered index which is the table its self) are stored in separate locations, they can have their own packing (space allowed for futher inserts without the tree becoming too unbalanced) and even be stored on separate drives: CREATE INDEX ....ON PRIMARY, SECONDARY etc. You have to create the SECONDARY and further files before creating the index and allocating to the File. Indexes are allocated to the logical file name. You can reduce costs and increase speed by having these as single rather than RAID drives, as in case of failure the index can be rebuilt without data loss. http://msdn.microsoft.com/en-us/library/ms188783.aspx and http://msdn.microsoft.com/en-us/library/gg492088.aspx