High server load with lot's of e-mails


I have setup a VirtualMin (GPL) server for a client. They want to send a daily email to 125+ users that consists of their schedule for the following day.

In our testing, sending one or two e-mails at a time is not problem, however, when the bulk blast to all 125+ addresses is sent, it sends the server load extremely high (goes up above 100). This occurs when Postfix hands the messages off to Procmail, and Procmail is running “lookup-domain.pl” on each message.

Unfortunately, because the server load goes high, this results in about 40% or more of the messages bouncing because the Procmail process times out.

I have disabled the spam and virus feature, so there is none of that going on. I have also set the “maxproc” in Postfix to 25, but since the call to “lookup-domain.pl” happens after Postfix hands the message off to Procmail, this doe snot help either.

Is there anything else I might be able to do? Is it necessary to call “lookup-domain.pl”, or can Procmail just deliver the messages on its own?

Thanks, in advance, for your help.




This email blast that’s being sent – is it being sent to local users, or users on another server?

The lookup-domain process would only be called when emails are being delivered locally… I just wanted to make sure that was what you were expecting.


In both cases it could help to configure Postfix to limit the speed of processing emails. There are numerous options to do that, this document should give a good overview: http://www.postfix.org/TUNING_README.html