Brenda,

The procedures can be found in the Server Administrators Guide.

Steps as follows.

Create space on filesystem (Nothing to do with TSM)
Use "dsmfmt" to create the DB files in the area you want.

Within TSM

Create DB volumes pointing to the files you just created,
Extend DB
Remove DB volume (original one.)

I am being simplistic, but it is well covered in the Admin Guide
(Available online from www.tivoli.com)

Rgrds

Richard