How to un-mount a volume forcefully

If you ever want to unmount a volume forcefully when the system does not allow, you need to find out who is holding on to the resource, terminate it and then unmount. This is very important to prevent data loss.

Who is holding on to the volume

# lsof | grep "/opt/download"


# fuser -cu /opt/data/System.log

Now terminate them

# kill -9

The PID will be determined from the fuser or lsof command above.

Now unmount the volume peacefully

# umount /opt/download

If you disregard who's active and want to unmount right away,

  # fuser -km /opt/download

In case, you want to unmount a NFS volume that is unreachable, try this.

# umount -f /opt/download

Done...