Would it be possible to say if this performance is sending or
receiving mail?
It is receiving mail (time to finish the smtp dialog)
Either way, show the `delays='' logging, which
reports the time spent in different stages of delivery.
The format of the "delays=a/b/c/d" logging is as follows:
o a = time from message arrival to last active queue
entry
o b = time from last active queue entry to connection
setup
o c = time in connection setup, including DNS, EHLO and
STARTTLS
o d = time in message transmission
delay=0.51, delays=0.21/0/0.17/0.13
I suspect that your mail sending program is too slow. You can test
Postfix raw speed with smtp-source test program, part of the Postfix
source bundle.
time smtp-source -4 -m 20 -S Test -l 500 -t u...@xxx.yy 127.0.0.1
real 0m4.097s
user 0m0.007s
sys 0m0.017s
So one thread delivers 5 mail/sec to postfix. Multiple threads scale
well, but single thread performance seems really low.
regards
Nikolai
