Recently I had a situation on one of my amazon EC2 instance that, I had to unmount a device from a server(amazon ec2 instance) and attach it to another instance. For that, I removed the entry from /etc/fstab file and tried running the following command.
sudo umount /mnt
But I got an error saying that I cannot unmount the device as the device is busy. After searching for a long time I found a solution. I run the following command and it worked.
sudo fuser -km /mnt/share
