今天shutdown immediate关数据库的时候出现ORA-01089: immediate shutdown in progress - no operations are permitted的错误。
ps -ef|grep ora_发现oracle的各个后台进程仍然在运行着，说明数据库没有关闭成功。
解决方法如下：
先exit退出，重新登录：
[oracle@localhost trace]$ sqlplus /nolog

SQL*Plus: Release 11.2.0.1.0 Production on Thu Sep 18 08:21:53 2014

Copyright (c) 1982, 2009, Oracle. All rights reserved.

@ 18-SEP-14>conn /as sysdba
Connected to an idle instance.
接着，使用shutdown abort强制关闭数据库：
SYS@orcl 18-SEP-14>shutdown abort;
ORACLE instance shut down.
最后，使用startup force打开数据库：
SYS@orcl 18-SEP-14>startup force;
ORACLE instance started.

Total System Global Area 849530880 bytes
Fixed Size 1339824 bytes
Variable Size 641732176 bytes
Database Buffers 201326592 bytes
Redo Buffers 5132288 bytes
Database mounted.
Database opened.

打开数据库之后，再次使用shutdown immediate关闭数据库：
SYS@orcl 18-SEP-14>shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
问题解决。