expdp ORA-39070：Unable to open the log file

Oracle中，当执行expdp或impdp的时候，有时候会出现错误：

[oracle@bi-dw ~]$ expdp dp_user/dp_password@dw directory=expdp_dir dumpfile=odi_work_dw.dmp logfile=odi_work.log  schemas=odi_work

Export: Release 12.1.0.2.0 - Production on Thu Dec 10 11:36:18 2015

Copyright (c) 1982, 2014, Oracle and/or its affiliates.  All rights reserved.

Connected to: Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production

With the Partitioning, OLAP, Advanced Analytics and Real Application Testing options

ORA-39002: invalid operation

ORA-39070: Unable to open the log file.

ORA-29283: invalid file operation

ORA-06512: at "SYS.UTL_FILE", line 536

ORA-29283: invalid file operation

产生这个错误的原因通常有两个：

     1、对存放dmp文件或log文件的路径不存在，或者没有权限,

      2、对dmp文件没有权限。

所以，遇到这个问题，首先去检查数据泵目录对应的操作系统目录和权限。

SQL> create or replace directory expdp_dir as '/bi/oradata_export';

经过检查，发现数据泵目录expdp_dir 对应的操作系统路径/bi/oradata_export不存在，新建即可