Mailscanner scanning slowly

Daníel Kristinn Gunnarsson danielg at
Tue Mar 3 15:30:40 GMT 2009

DNS seems to be okay, average scan is about 3-5 secs using spamassassin -D dns < sample_spam - I'm caching DNS locally as well.

Daniel Kristinn Gunnarsson
Tæknimaður / Technician
Tækniborð / Technical Support
danielg at
+354 599-9500 - 3 

Skútuvogi 2
104 Reykjavík


-----Original Message-----
From: mailscanner-bounces at [mailto:mailscanner-bounces at] On Behalf Of Alex Broens
Sent: 3. mars 2009 15:18
To: MailScanner discussion
Subject: Re: Mailscanner scanning slowly

On 3/3/2009 4:03 PM, Daníel Kristinn Gunnarsson 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.

with that hardware, 50k msgs aren't heavy traffic.

Could be DNS lag.

Run a spam message thru spamassassin with -D dns:

spamassassin -D dns < sample_spam

that should make it clear if you have a DNS issue and can rule that out.

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