NFS Server Hangs, NFS Client Hangs

I woke up this morning to a disk alert from a server.

Assuming it was a disk-full alert, I run a df -h and it hangs. I then Ctrl-C and try to list individual mount points to check which one is at fault, and it turned out to be an NFS mounted volume.

At this point, I just needed the server alert to go away and the NFS share was only being used for moving files so I attempt to unmount /mnt/nfs_share but that hangs too. I then see that there’s a -l (lazy) option for exactly this scenario - the man page says that if the network share is not reachable, umount will hang so use the -l.

umount -l /mnt/nfs_share