>The process is very slow and cause a lot of mount of tape volumes

Valeriano - A variety of factors are involved....

Your collocation specification can cause many tapes to be mounted as
files are "delivered" to their appropriate places in the next
storage pool.  Database cache hit ratio performance will govern the
speed at which the *SM database will participate in the movement of
all the files.  Long mount retention periods can aggravate processing
in having to dismount a tape before the next one can be mounted.  And
the MOVEBatchsize and MOVESizethresh server option values will govern
how much data moves in each server transaction.  The performance of
your tape technology is also a factor.
   Richard Sims, BU