Mail get stuck in the mailing queue

[Edwin Kliest]

Every morning I have about 400,000 emails waiting in the mailing queue. The server receives about 100,000 emails per hour, but it only sends out between 10,000 and 30,000 emails per hour. I have tried to fine tune the exim.conf file, to handle more emails, but I have not been able to let it email more per hour.

The server that is used is a Dual Xeon pentium 3.06 ghz, and is using hyperthreading.

Here are the changes I have made in the exim.conf file:

#nobody as the sender seems to annoy people
untrusted_set_sender = *
local_from_check = false

rfc1413_query_timeout = 10s


smtp_connect_backlog = 100
smtp_accept_max = 20000

queue_run_max =7000
remote_max_parallel = 1000
queue_run_in_order = false
split_spool_directory = true
queue_only_load = 35
smtp_load_reserve = 35
smtp_receive_timeout = 5m
smtp_accept_queue= 35
smtp_accept_max_per_connection = 30000
smtp_accept_keepalive = true
recipients_max = 50000
smtp_accept_queue_per_connection = 15000
deliver_queue_load_max = 35
auto_thaw = 0s


Any suggestions are very welcome,

Thanks,
Edwin Kliest

[Tony Marques]

Post by Edwin Kliest
auto_thaw = 0s
Any suggestions are very welcome,

No one should be using auto_thaw, but if you are, then set it to
something like 1d or something more appropriate to give it a chance to
breath, and always set ignore_bounce_errors_after to a smaller (or
perhaps equal) value, so set that to 1h to clear out undeliverable
bounces (messages you created).

With auto_thaw but no ignore_bounce_errors_after, then you will be
trying to deliver bounce messages dispite getting 550 errors....
you'll be trying to deliver messages for several days despite getting
550 User Unknown or 550 Virus found responses... are you prepared to
wait for the user to exist? or perhaps you really want to deliver that
virus?

Auto_thaw only applies to frozen messages -- messages that are
undeliverable. If you can't connect to a remote host and most other
problems, messages aren't frozen, they will remain in the queue,
deferred. It is only after 4 days of connection problems or a
response like 550 User Unknown/550 Virus/550 Spam Content that will
freeze a message -- why you would want to use auto_thaw on these
messages is something you really should consider. It is better to use
timeout_frozen_after and bounce them. If you wanted to keep on trying
to deliver messages, extend the retry time in the retry rules and just
don't freeze them so fast. If you think auto_thaw speeds up delivery,
you should again be adjusting the retry rules to retry more often.

ignore_bounce_errors_after = 1h
So, don't use auto_thaw (ever)
tweak retry rules instead
timeout_frozen_after = 7d

This should prevent undeliverable messages from consuming so many
resources and perhaps slowing down your system.


Meanwhile, to speed up general operation use a local dns server or set
one up if you haven't already.

[Jakob Hirsch]

Post by Tony Marques

Post by Edwin Kliest
auto_thaw = 0s

No one should be using auto_thaw, but if you are, then set it to

That's right, but 0s is default setting, meaning it is disabled.