So I just benchmarked Haraka vs Qpsmtpd. Both were using minimal config (accept all mails, don’t write to disk) so this is really only testing the core frameworks. Both were using async I/O (using qpsmtpd-async). Both single process on my iMac.

Results, qpsmtpd first:

matt@Valour ~/Perl/node$ time /usr/libexec/postfix/smtp-source -l 5000 -m 50000 -s 100 -d -f matt@local -t matt@haraka.local -c localhost:2525 50000 real 1m28.451s user 0m1.789s sys 0m6.357s

And Haraka:

matt@Valour ~/Perl/node$ time /usr/libexec/postfix/smtp-source -l 5000 -m 50000 -s 100 -d -f matt@local -t matt@haraka.local -c localhost:2525 50000 real 0m12.020s user 0m1.730s sys 0m6.351s