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Nenad
Asked: 2011-12-15 08:28:16 +0800 CST

Postfix tuning for high amount

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I have do some benchmarks with postfix, where we send out 6 KB HTML Mails. We followed all tuning instructions published by Postfix and used Ramdisk for the queue.

We were not able to send above 50 Mails / sec out.

Does anyone have some input on how we can improve that number?

The Server is only used for outgoing Mails.

Only to mention: I'm not a spammer :-) We will use it for a dating site where we send a big amount of Mails out for Notifications, weekly reports, daily stats.

postfix email-server tuning

2 Answers

  1. It sounds like you need greater concurrency.

    First ensure that you aren't bound by disk activity. atop is a good interactive method for this. sar and other tools are available as well. Given the ramdisk, this shouldn't be the major issue.

    If your queue is full of mail going to many different domains, that is a sign that you aren't running enough server processes. Bump the limit on how many smptd instances you spawn.

    If your queue is full of mail to some of the big internet sites (tons of GMail, for example), you will need to tune your settings for single-host delivery. Postfix should ramp itself up if it has a lot of email to the same domain, though.

    Investigate and let us know what you're seeing.

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  2. Having a DNS caching server on the mail server will help speed up deliveries as well. In fact, there have been many times in my environment where DNS lookups were THE bottleneck for mail delivery.

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