Hi Michael,
You can refer to 489690 - CC INFO: Copying large production clients.
My 2 cents, copying Production data on DEV clients is not a very good idea. In case you need some specific data for Unit testing there is a tool called TDMS (Test Data Migration Service) where you can select the relevant BPL and copy the data. If you don't have TDMS you can also use you Solution Manager system provided it has the DMIS addon.
You can change the DIR_TRANS to a shared location which has enough space (this will need a restart of the application) for both DEV and Prod and proceed.
Thanks,
Manas