These forums are locked and archived, but all topics have been migrated to the new forum. You can search for this topic on the new forum: Search for Postfix Quota Warning on the new forum.
In Exim, you can set the server up to send quota warnings every easily for when a user gets within, say, 90% of their account quota. Exim will automatically deliver a warning email to their Inbox.
I cannot figure out how to do the same with Postfix. Any ideas?