I'm not sure what happened but I used to be able to backup to a drive shared with a networked Mac Mini using OSX server. Now all of a sudden it says there is not enough space.
So I reformatted the drive (12TB) and restarted the whole thing. However Time Machine now tell me there is not enough space. It says:
The backup disk needs 5.35 TB for the backup but only 499.49 GB are available.
I'm not sure why only 499GB is available.