This is a bit strange. I have a ZSH mounted network directory in a Redhat VM and it appears to be shrinking:
[aramk@server-C production]$ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda1 8.7G 7.2G 1.1G 87% /
tmpfs 1.9G 0 1.9G 0% /dev/shm
myserver:/mypath
3.0G 2.9G 74M 98% /mnt/mydir
[aramk@server-C www]$ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda1 8.7G 7.2G 1.1G 87% /
tmpfs 1.9G 0 1.9G 0% /dev/shm
myserver:/mypath
2.9G 2.8G 74M 98% /mnt/mydir
[aramk@server-C confluence]$ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda1 8.7G 7.2G 1.1G 87% /
tmpfs 1.9G 0 1.9G 0% /dev/shm
myserver:/mypath
2.5G 2.4G 74M 98% /mnt/mydir
[aramk@server-C ~]$ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda1 8.7G 7.2G 1.1G 87% /
tmpfs 1.9G 0 1.9G 0% /dev/shm
myserver:/mypath
2.3G 2.3G 1.0M 100% /mnt/mydir
I was forced to use this method to remove some files, but then I removed too much and it shrank again from 3GB to 2.4GB. The original drive was 10GB and shrank down to 6GB and then to 3GB as I removed unnecessary files. Any ideas?