umount: /mnt/cdrom: device is busy

umount: /mnt/cdrom: device is busyEvery wonder why sometimes you get this message

when you try to un-mount a NFS drive or cdrom drive

CODEroot@homer:~# umount /mnt/cdrom

umount: /mnt/cdrom: device is busy
umount: /mnt/cdrom: device is busy
root@homer:~#

Well chances a process is running that is using that directory. To find out run

CODEroot@homer:~# fuser -m /mnt/cdrom/
/mnt/cdrom/: 24066c

That shows you what process is using that directory. Now lets do a ps aux and see

whats running

CODEroot@homer:~# ps aux | grep 24066

root 24066 0.0 0.5 2244 1284 pts/10 S 14:04 0:00 -su
root@homer:~#

Looks like a the root user is in that directory. If you cannot find the term that is

in that directory then kill that process

CODEroot@homer:~# kill -9 24066
root@homer:~#

now you can un-mount

CODEroot@homer:~# umount /mnt/cdrom/
root@homer:~#

This tip brought to you by the letter J and the letter Y