OCI: The “df -hT” Command Hangs

Applies to:  

Oracle Cloud Infrastructure - Version N/A and later 

Symptoms:

OS level command like df -hT are hanging or provide no output.

Cause

The issue is due to a decommissioned NFS mount, but the NFS  mountpoint on the Client is 

still mounted.

It can be checked with:

# findmnt | grep -i nfs
TARGET                                SOURCE                                                   FSTYPE      OPTIONS
/nfs-mountpoint                nfs-server:/shared-nfs-filesystem       nfs         
rw,noatime,vers=3,rsize=1048576,wsize=1048576,namlen=255,hard,proto=tcp,timeo=600,r
etrans=2,sec=sys,mountaddr=10.x.x..x

The following commands hang:

# df -hT
# lsof /nfs-mountpoint
# fuser /nfs-mountpoint

Solution

Attempt  to forcibly unmount the filesystem:

# umount -f /nfs-mountpoint
If the above command hangs or fails, retry with the “-l” option:
# umount -l /nfs-mountpoint