Limit data traffic on Apache virtual hosts
I would like to limit the amount of data traffic that is generated by the virtual hosts on my server:
Let's say I want to allow most domains 1 GB of traffic per month and I would like to generate a warning when they reach 900 MB and shut the site down when it reaches 1 GB (unless my customer purchases additional traffic).
Is this possible? And if so, does anyone suggestions on how to do this?
Thanks in advance!