MailScanner load

Steve Campbell campbell at
Wed Aug 16 21:20:12 IST 2006

Decided to make an intelligent statement this time:

One thing I did find to lower my load average, though, was MimeDefang in a 
look-ahead environment.

Before installing MimeDefang,  I was receiving about 25K messages a day per 
server. Most of those were secondary MX relays, that is, mail sent to the 
secondary MX by spammers, and then relayed to the primary MX or mail store. 
I just use the look-ahead function in MD, nothing else. The load average was 
slowly climbing into the 8+ range and higher as a norm. After the install, 
my message count dropped to around 10K a day, and the load average dropped 
to around 2-3 as a norm. It still shoots up once in a while, but nothing 
like before MD.

Obviously, running MD will add overhead, but the drop of about 60% emails 
needing to be scanned more than made up for that. I then was better able to 
detect more hosts/IP to add to my MTA access file, which made things even 

Another thing to mention is that before and after, mail ran smoothly. It 
just took a little bit longer before installing MD as there were always more 
processes (sendmail) trying to deliver DSN mail and the likes.

This is not an answer for all systems - it's just that I use my MXs in a 
bazaar way (I think). My primary MX for one domain is a secondary MX for 
another domain. The primaries hold the mailboxes for their domain.

No smiley face statements here.

Steve Campbell
campbell at
Charleston Newspapers

----- Original Message ----- 
From: "Julian Field" <mailscanner at>
To: "MailScanner discussion" <mailscanner at>
Sent: Wednesday, August 16, 2006 2:27 PM
Subject: Re: MailScanner load

> Hash: SHA1
> Steve Campbell wrote:
>> ----- Original Message ----- From: "Alex Neuman van der Hans"
>> <alex at>
>> To: "MailScanner discussion" <mailscanner at>
>> Sent: Tuesday, August 15, 2006 4:41 PM
>> Subject: Re: MailScanner load
>>> You *do* know that MailScanner causes swap, don't you? ;-)
>> When did this start happening????????
> Like any other package, it will start to swap if you run out of RAM. It
> does not "cause" swap.
>> Steve
>>> Rob Poe wrote:
>>>> What's your swap utilization?  1gig of ram using tempfs and MailScanner
>>>> sounds like too little ram...
>>>>>>> "Jeremy Blonde" <JeremyBlonde at> 8/15/2006 1:26 PM
>>>> I've been wanting to use Bayes for our mailscanner system, but I'm
>>>> wondering now if the overhead is worth it.  We have a new mailscanner
>>>> box running with Postfix (under Gentoo Linux) and it works pretty
>>>> well,
>>>> we're filtering between 75-80% of our mail as spam.  The box however,
>>>> is
>>>> hammered, it's running around 5-6 with spikes to 8-9.  I've just
>>>> turned
>>>> off bayes and I'll see how the load is once it's processed all the
>>>> back
>>>> logged messages.  We're averaging about 15,000-20,000 messages a day
>>>> (probably more once the school year starts).  Mailscanner is running
>>>> on
>>>> an HP DL320, hyper-threaded proc, 1 GB of RAM, and raid 1 drives.
>>>> Is that normal for using bayes with mailscanner or do I need to tweak
>>>> some things?
>>>> (I'm already using tmpfs for a little bit of a speed up).
>>>> Jeremy Blonde
>>>> Instructional Technology - Server Support
>>>> Grant Joint Union School District
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> - -- 
> Julian Field
> Buy the MailScanner book at
> MailScanner customisation, or any advanced system administration help?
> Contact me at Jules at
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