Can Data Pump Be Used Against Multiple RAC Instances in Parallel?

The simple answer is no, unless you’ve got a shared file-system on which to put your dump and log files.
Here’s what happens if not:

 

If we create the same directory name on both servers in a cluster, it’ll work a little bit further but still ultimately fail:

 

 

Of course, if we had both servers NFS-mounted to a shared file-system with the appropriate mount options, it should work.