High loads with EXIM, when Mailman lists used

[ttremain]

We typically run "release" and this started about 2 weeks ago, on multiple servers.

A couple of our clients have larger mailing lists, or multiple smaller mailing lists that
only they can send to.

When a mailing is sent via these lists, server load, can easily jump from .10 to 30 or 40.
Exim is at that point running several tasks at 99% load.

These lists had no problem until receintly, and have been tested at much lower output than
normal, with bad results. (high loads, Apache can't be reached, or too slow to respond, etc)

We are at our wits end here, and would love some ideas.

[chirpy]

A few ideas:

1. Make sure that you're using a local DNS resolver in /etc/resolv.conf and not a remote one

2. Disable sender callouts in WHM > Exim Configuration Editor

3. You can offload email to the queue on high loads by adding the following to the first textarea of the advanced mode exim config editor:

queue_only_load = 6

[ttremain]

I'll certainly try #'s 2 and 3 right now.

The first resolve server we use, is on the same VLAN, but not part of
the same DNS cluster. This makes it close, but public settings are
not overridden by the local DNS.

Thanks!

[budway]

It`s actually said to deal with mailman it does not troutle it`s load/sent.

If all your customers send 1.000.000 e-mail mailman will actually try to send all these e-mails in a fly.

It`s actually said!

[chirpy]

I'm afraid I don't understand your update. Are you asking a question about something related to this thread?

If you're talking about the fact that mailman doesn't rate limit mail sending, that is true, but you can tweak both mailman and exim to prevent large mailing lists bringing your server to a stop.

[ttremain]

After disabling callouts, and setting queue_only_load, we are now getting nothing but complaints from our client.

"how come our email isn't as quick as it was two weeks ago?" Mind you, two weeks ago we didn't have load issues, either...

I believe something serious has changed in either exim or mailman.

[lloyd_tennison]

Some exim update has changed server load as I am also seeing this in the last week or so. Exim is uses more resources than it has been especialy with Mailman even with Mailman throttled.

Have to wait to either Exim 4.54 or re-setup Mailman limits. I know I am going to resetup limits as have no idea on 4.54.

[MichaelShanks]

there is defiently a problem with exim, i'm noticing high load on about a dozen servers, all mail process's, killing off spamd seems to help

[MichaelShanks]

http://bugzilla.cpanel.net/show_bug.cgi?id=3530

[ttremain]

I have added to the ticket.

Thanks!

[ttremain]

Killing off spamd (disabling Spamassassin in tweak settings, and service manager) does not seem to make any difference here.

[jondolar]

I have a very similar issue but I can't narrow it down to any mailing list.

Exim starts increasing cpu utilization (as displayed in top) to 99% and then kicks off another exim process. After a few minutes, that process jumps to 99% and then another exim process starts. Ater about 1/2 hour I have 6 or 7 exim processes and the server load is sitting at about 10 (up from 1 to 2). If I let this go exim will keep kicking off more processes until the load crashes the server.

I have a cron job to restart exim every 1/2 hour and that "fixes" the issue with the load. However, this is obviously not a permanent solution.

This is so consistent and is happening over 5+ days. It starts happening immediately after a reboot as well. It looks like there is something causing the exim process to "hang" and it starts another process which eventually "hangs" as well.

Do you think this is related?
Any thoughts?

[ttremain]

This could very well be closer to the cause than any of us have gotten.

It may or may not be related, but does sound very much like what I am seeing.

As an added note, in the process however, very little mail is actually getting sent per minute/hour.

[chirpy]

Have you tried running a strace on the pd to find out what, exactly it is doing?

[MichaelShanks]

I have a very similar issue but I can't narrow it down to any mailing list.

Exim starts increasing cpu utilization (as displayed in top) to 99% and then kicks off another exim process. After a few minutes, that process jumps to 99% and then another exim process starts. Ater about 1/2 hour I have 6 or 7 exim processes and the server load is sitting at about 10 (up from 1 to 2). If I let this go exim will keep kicking off more processes until the load crashes the server.

I have a cron job to restart exim every 1/2 hour and that "fixes" the issue with the load. However, this is obviously not a permanent solution.

This is so consistent and is happening over 5+ days. It starts happening immediately after a reboot as well. It looks like there is something causing the exim process to "hang" and it starts another process which eventually "hangs" as well.

Do you think this is related?
Any thoughts?

try disabling spamd, 70% sure this will fix it, kill off cheksrvd first though so cpanel doesnt bring it up,

there is defiently a problem with cpanel, i have gone from stable servers to having half a dozen having problems, this happened in the space of one night and killing off spamd brings them under control

by bugzilla report was dismissed stating "not much we can do as we can't recreate locally"