expdp stops with status DEFINING when export to NFS filesystem
                                                 Last update (2011-06-04 13:55:06)
                                                                                                                   Date added (2011-06-04 13:26:02)

Summary
Trying to use oracle data pump to export some data to a file system which is NFS and the exdp hangs with status DEFINING

If you try to stop the running data pump job and try to clean the orphaned master control queues like it is described in Metalink Note: 336014.1 How To Cleanup Orphaned DataPump Jobs In DBA_DATAPUMP_JOBS you will see that you cannot kill the ora_dm* oracle process that is related to the data pump export. This process cannot be killed even though trying as a root.

The data pump job is in status DEFINING and the wait event related to the session is wait for unread message on broadcast channel waiting for ever!

If you try the same expdp but to store the dump file and log file to a non NFS filesystem (for example to a local disk or SAN), then the export succeeds!

Oracle has spotted the case as:
Bug 6433651: JOB HANGS IN DEFINING STATUS WITH FILE ON 4K SIZE USING NFS MOUNT POINT.
Basically according to Oracle the NFS mounting options are not correct, you can check the ORA-27054 NFS file system where the file is created or resides is not mounted with correct options" [ID 338086.1]

Workaround: Oracle recommends to set the init parameter

alter system set event = '10298 trace name context forever, level 32' scope=spfile;

which disables the NFS mount option checking.