The server and client are both using Ubuntu 16.04.  I have setup both Samba and NFS on the server.  I have installed both cifs-utils and the nfs utils on the client.

When I run `df -h` on the server I get the following output:

terrance@terrance-ubuntu:~$ ssh 10.0.0.220 'df -h'
/dev/md1p1       15T  7.4T  6.4T  54% /media/storage

Then I go and set up both mounts on my client for testing:

terrance@terrance-ubuntu:~$ df -h
10.0.0.220:/media/storage   15T  7.4T  6.4T  54% /media/NAS
//10.0.0.220/storage        15T  8.1T  6.4T  57% /cifs/server

The first one listed above is the NFS mount.

As a test last night I copied an 18GB file to my server and the CIFS mount reported now 8.4T used.  When I deleted the file it went back to 8.1T used.  There is no way 18GB = 300GB.

What is the reason for the discrepancy in the used size calculations for the CIFS mount?  

Thank you!