Mailscanner scanning slowly

Jason Voorhees jvoorhees1 at
Tue Mar 3 18:43:37 GMT 2009


On Tue, Mar 3, 2009 at 10:03 AM, Daníel Kristinn Gunnarsson
<danielg at> wrote:
> Hi there !
> Lately I've been running into some trouble with MailScanner + spamassassin. Let me explain my current setup.
> I have a high-load mailserver (100k+ emails per day) that transfers all emails to 2 dedicated servers running Mailscanner + spamassassin for scanning. Both machines have the exact same setup:
> SLES 9.3
> 4gb RAM
> 2x 64-bit Dual Core AMD Opteron running at 2ghz
> MailScanner 4.71.10
> SpamAssassin 3.2.5
> Perl 5.8.3
> Postfix 2.2.6
> Both servers process almost equal amount of mail or about 50k each. The problem I'm having is that while server 2 is processing 10 mail scans in about ~60 secs, server 1 takes 300 secs to process them. Max unscanned and max unsafe messages per scan is set to 10 messages, no RBL checks set in MailScanner.conf, 10 children running and Delivery method is running in Batch, changing it to queue did nothing for me. I've tried lowering max children and messages per scanning batch but still it takes from 5 secs to 1 minute to scan a single message on server 1. CPU load goes from 0.4 to 0.8 on both servers. Any ideas, thoughts, tips and tricks are appreciated.

I suspect that is SpamAssassin who is working slowly. Have you tried
to disable Spam Checks and then compare how much time takes
MailScanner to scan messages? You could use a rules file to disable
spam checks only for a couple of test sender e-mail addresses.

You can confirm how much time is SpamAssassin spending on scanning
messages doing some local scans manually:

$ time spamassassin -L < /path-to/test-spam-message

Then run the same test again without -L flag and compare.

What special SpamAssassin settings do you have? What plugins are you
using? Could you try disabling some of them.

Share with us some of your tests and results
> Daniel Kristinn Gunnarsson
> Tæknimaður / Technician
> Tækniborð / Technical Support
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