Well - it sounds like you are planning a DR test? Your DB backup needs to be referenced by the device config file that will be used by the DB restore process. In a nutshell, the "dsmserv restore db" command will look in the dsmserv.opt file to find out where the volume history and device configuration files are stored. The volume history file will provide the volume containing the relevant DB backup, whilst the device configuration file will provide the location in the library that stores that volume - think of it as a file-based equivalent of the library volumes table. So - insert the DB backup in a slot, not a drive.
One quick way to build the device configuration file you need is to initialize a basic instance of TSM using "dsmserv format". You need to be careful with environment variables, file locations, etc, but you can quickly generate a devconfig file that will provide the information your restore process will need.
HTH
Kind Regards,
Matthew Bourne
"Find a job you love and never do a day's work in your life.