使用expdp时报错：
ORA-39002: invalid operation
ORA-39070: Unable to open the log file.
ORA-29283: invalid file operation
ORA-06512: at "SYS.UTL_FILE", line 475
ORA-29283: invalid file operation
发现原因如下：
SQL> create or replace directory dpdata
2 as '/home/Oracle/backup';
Directory created.
发现原来他的目录设错了。只要将路径设好，再授权一下就可以。