Quite a mess you have there.  I'd take the initial approach of using dsmfmt to
try to recreate the new volume that was discarded, add it to dsmserv.dsk, then
try restarting the server.  (Remember: the database itself remembers its
volumes, so meddling can be counter-productive.  External files like
dsmserv.dsk are there to facilitate recovery operations.)  If that doesn't
work, you'll likely have to do a db restoral.
    Richard Sims, BU