Here at the BIC, NFS shares are handled via autofs …
Autofs is a linux service that manages mount points as needed: it only mounts a given mount point (NFS share) when that share is accessed and it will be unmounted after a defined period of inactivity (currently set to 5 minutes).
the keyword here is unmounted, hence it will no longer be listed by commands like ls or df …
here’s an example:
$ cd /data/scratch
$ ls -al
total 0
drwxr-xr-x 2 root root 0 Nov 27 14:13 .
drwxr-xr-x 24 root root 0 Dec 12 10:56 …
$ df -h scratch1
Filesystem Size Used Avail Use% Mounted on
nfs.isi.bic.mni.mcgill.ca:/scratch1 25G 4.0G 22G 16% /data/scratch/scratch1
$ ls -al
total 2
drwxr-xr-x 3 root root 0 Dec 13 13:00 .
drwxr-xr-x 24 root root 0 Dec 12 10:56 …
drwxrwxrwt 3 root wheel 31 Dec 13 06:00 scratch1