Umount cannot be a disk or network device

Umount cannot be a disk or network device
Umount cannot be a disk or network device

For example, umount cannot run/g01/app/shared

[root@rac01 shared]# umount /g01/app/sharedumount.nfs: /g01/app/shared: device is busyumount: /g01/app/shared: device is busy.        (In some cases useful info about processes that use         the device is found by lsof(8) or fuser(1))umount.nfs: /g01/app/shared: device is busy

You can use-l to force umount,

umount -l /g01/app/shared

But there is a way to check who is using this device, the method is very simple
Fuser

[root@rac01 shared]# fuser -u /g01/app/shared/g01/app/shared: 1520c(root)[root@rac01 shared]# ps axu|grep 1520root 1520 0.0 0.0 108468 1912 pts/0 S 09:00 0:00 bashroot 1630 0.0 0.0 103256 840 pts/0 S+ 09:09 0:00 grep 1520

After ps, check the process and find that the bash process is in use. Exit the Directory and umount will be OK.