I’ve recently needed to add disk usage quotas to a server in order to limit how much data users can store so as not to affect the quality of service for other users.
Linux has a method called quota which can help you do this.
Ubuntu provides some packaged tools which let you manage quotas
apt-get install quota
To enable quotas on a partition the first step is to edit the /etc/fstab entry for the partition and append usrquota to it so the kernel knows to manage that partition using quotas.