During the course of last night, the IT Division's management server had a failed hard disk and crashed.
Amongst other things, this machine is responsible for making decisions about the access control lists used in the Internet Quota System. This means that, until the machine is properly restored, the access lists that make up the quota system will not be updated; people who're denied access will continue to be denied access even if the legitimately drop below the threshold. No data will be lost by the quota system -- all downloads that happen in the interim period are logged by the caches and quotas will be automatically recalculated once the machine comes back up.
The machine also hosts the graphs displayed on http://www.ru.ac.za/quotas/ as well as http://graphs.ru.ac.za/. These graphs will not be updated during the course of the outage.
As the machine is a new one (it was installed during the course of last week), we're in the process of running diagnostics on the failed hard disk(s) to try and work out what happened. This may take some time to complete, and full service may only be restored during the course of Monday.