If you never delete your volhist, you can search it to track the number of times the volume has been assigned to a storagepool. This won't track usage as a TSM DBBackup, but if you're willing to be close but not exact, you can use it.
If you want to track mounts, you need something external. A good perl programmer and a reusedelay of 1 day on all storage pools can get this information. Nick Cassimatis [EMAIL PROTECTED] He who laughs last has a good backup.