The number of parallels is usually determined by the number of CPUs. For example, below are 2 parallel data pump exports.
1 | -bash-3.2$ expdp "'/ as sysdba'" directory=dump_dir schemas=scott dumpfile=scott1.dmp,scott2.dmp logfile=scott.log reuse_dumpfiles=y parallel=2 |
We can also provide automatic dumpfile creation as much as the parallel number.
1 | -bash-3.2$ expdp "'/ as sysdba'" directory=dump_dir schemas=scott dumpfile=scott%U.dmp logfile=scott.log reuse_dumpfiles=y parallel=2 |