NFS: How to unmount nfs that already inaccessible?

Sometime when you login to server and going to use df -h under ssh command, you will facing hang and server does not show any information under df -h command. How to deal with it?

It is likely the issue due to nfs that already sync with the client but nfs server gone. So nfs client (your server) still reading and wait for the connection.

To solve this, use this command :

umount -f -l /mnt/nfs/kvm-backup

This will help you to detach nfs and able to use df -h again.