执行umount 命令的时候出现 device is busy ，有人在使用这块磁盘
umount /dev/sde1
umount: /u01/app/oracle: device is busy
umount: /u01/app/oracle: device is busy
使用fuser 命令查看哪个进程在使用
[root@localhost ~]# fuser -m /u01/app/oracle/
/u01/app/oracle/: 2636c 2694c
[root@localhost ~]# ps aux | grep 2636
root 2636 0.0 0.2 4532 1464 pts/1 S 09:56 0:00 bash
root 2776 0.0 0.1 3916 696 pts/1 R+ 10:18 0:00 grep 2636
kill -9 干掉进程
[root@localhost ~]# kill -9 2636
[root@localhost ~]# umount /dev/sde1