It seems that out of the box, OpenVZ with cPanel, disk quotas do not work. You can set quotas on clients accounts inside the WHM, but they don’t actually calculate, so essentially, everybody on that server has unlimited disk space.
To correct this, you need to make the following changes on the VPS hardware node.
For this example, we’ll assume the customers VEID or CTID is 100
1. Stop the customers container
vzctl stop 100
2. Edit the containers config file
vi /etc/vz/conf/100.conf
3. Add or edit the following lines to match this:
quotaugidlimit="10000"
quotatime="1"
disk_quota="yes"
4. Save the changes
5. Delete the current quota file
rm /var/vzquota/quota.100
6. Restart the customers continer
vzctl start 100
Now if you login to the container, you can run /scripts/initquotas
and /scripts/fixquotas
successfully.