We have a mail server setup using instructions from www.shupp.org/toaster. For each virtual domain hosted on this server, we enter a new mysql record in the limits table to define the domain quota.
We notice that all mails start to bounce once the domain size reaches approximately 2Gb. Once we modify the mysql record to allow the domain quota to be unlimited, the problem goes away.
Is this a known problem? If so how best can this be circumvented?