I'm not clear on the problem definition, but if it is that two
volumes are being used for the backup when you believe that only one
should be, it could well be due to files being associated with a
management class whose retention is modest compared to another policy
set management class, where the latter will by default be used for
directories, as outlined in the client manual. This is particularly
an issue for Windows, where the directory entries are "rich" and so
have to be stored in a storage pool, rather than simply in the TSM
db.  You can use the Query CONtent command with a negative Count
value to inspect what type of objects are ending up on each volume.

   Richard Sims