Sometimes when you try to unmount a mounted filesystem in Linux, it gives an error that can not unmount device, device or resource busy. Now to deal with such situation do the following:

Suppose a partition /dev/sdb1 is mounted to directory /storage and you are trying to unmount it.

[root@localhost ~]# umount /storage

umount: /storage: device is busy
umount: /storage: device is busySolution : Use the lsof command to find the pid and the open files used by /storage
[root@localhost ~]# lsof | grep /storage
esd       23711   root  cwd       DIR       8,17      4096    1228794 /storage720p BRRip x264 – HDMiCRO by Mr. KickASS
esd       23711   root    3r      REG       8,17 942758269    1229005 /storage/ – HDMiCRO by Mr. KickASS/ Mr. KickASS.mp4

Once you get the pid just kill it.
[root@localhost ~]# kill -9 23711
[root@sandbox1 ~]# umount /storage
Done.
Posted in: Linux.
Last Modified: October 23, 2013

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