How well does Exim scale?
A0702: Although the author did not specifically set out to write a high- performance MTA, Exim does seem to be fairly efficient. The biggest server at the University of Cambridge (a large Sun box) goes over 100,000 deliveries per day on busy days (it has over 20,000 users). There was a report of a mailing list exploder that sometimes handles over 100,000 deliveries a day on a big Linux box, the record being 177,000 deliveries (791MB in total). Up to 13,000 deliveries an hour have been reported. These are quotes from some Exim users: “… Canada’s largest internet provider, uses Exim on all of our mail machines, and we’re absolutely delighted with it. It brought life back into one of our machines plagued with backlogs and high load averages. Here’s just an example of how much email our largest mail server (quad SS1000) is seeing … ” [230,911 deliveries in a day: 4,475MB] “… Exim has to … do gethostbyname()s and RBL lookups on all of the incoming mail servers, and he runs from inet
