Doubts about PF, what are the pros/cons about other MTAs?

[Julian Field]

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Glenn, you make me blush :-)

Glenn Steen wrote:
> On 01/07/07, Mikael Syska <mikael at syska.dk> wrote:
>> Glenn Steen wrote:
>> > On 01/07/07, Mikael Syska <mikael at syska.dk> wrote:
>> >> Hey,
>> >>
>> >> Julian Field wrote:
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>> >> >
>> >> >
>> >> >
>> >> > Mikael Syska wrote:
>> >> >
>> >> >> [snip]
>> >> >> I think I'm convinced now ... I'm going to use postfix, since 
>> no real
>> >> >> arguments againts it have been made.
>> >> >>
>> >> >> Thanks for the time guys.
>> >> >>
>> >> > I'm going to release a new stable version tomorrow which 
>> includes the
>> >> > recent Postfix bugfix to do with its milter support.
>> >> > If you can't wait till tomorrow, then it's already on the website,
>> >> > you'll just have to guess the URL for 4.61.7-1 :-)
>> >> >
>> >> I can wait ... I wont begin on the server until tuesday ... So no
>> >> problems there.
>> >>
>> >> Can't wait to get my hands dirty converting the old amavisd-new setup
>> >> ... some other dude had setup it up, and its a real pain to figure
>> >> out ...
>> >>
>> >> Btw, read on a page on the internet where a person said that MS 
>> did not
>> >> use the resources very good cause its spawning a new process for 
>> every
>> >> mail and afterwards closing it. amavisd-new also did that in the 
>> start
>> >> but changed over to daemon style ... so its not spawning a new proces
>> >> every time ...
>> >> Is there something about this, or did the guy just not like MS ?
>> >> and if there are something about it ... will MS be changed to spawn
>> >> daemons ?
>> >> what are the pros/cons agints it ?
>> >>
>> > Don't belieeve everything said on the net....:)
>> > MS runs a master and several worker children, which all (incidentally)
>> > work in a daemon-like fashion, and these children will take turns
>> > popping messages from the queue ... They will take as many messages as
>> > necessary to form a batch (1 -> ...many messages) and work on these in
>> > a "group" way... So no "single process for every message" there:-).
>> > The worker children might in turn spawn children to run specific
>> > functions, like AV etc, but they will still work on the whole batch as
>> > such.
>> So whenever MS checks the mailqueue it takes all the mails in the queue,
>> and runs a batch agains them ? and then again in x seconds with a new
>> batch, taking mail that havent been handled?
> It's clever enough to keep track of which items is handled by some
> other worker, so ... Yes, it will only handle new items... It might
> look a bit strange when you have "New batch: Found 28 messages in
> queue" and then followed by running a batch with only one or two
> messages, but this is because other workers are handling the other
> queued messages.
> The decoupling of the scanning process fromthe SMTP transaction(s) and
> the batch strategy are some of the design decisions Jules made that
> really make things fly with MS.
>
>> > Very efficient, very slick.
>> If the above is right, this seems like its using the resources better
>> than amavisd-new maybe, but theese days Ram and harddrives are very
>> cheap, so if it just runs fast, i'm happy.
> Resource efficiency is one of the high points of MS... The activity of
> spam/av-scanning is resource hungry, by definition, so ... be happy
> that MailScanner is so cleverly come together;-).
>
>> > Of course, as with most things in MS, you can configure the amount of
>> > workers to prespawn, as well as most any aspect of the process...
>> > You'll see, once you start using it;)
>> Think this cleared any doubts i had.
> Good.
> When you set this up, there is a lot of good stuff in the MailScanner
> wiki... Specifics for MS+PF... and very much generally good advice in
> the MAQ (although since the faq-o-matic (old MAQ) has died again, some
> of the links in the new MAQ is plain dead). So have a long hard look
> at http://wiki.mailscanner.info, especially the
> documentation:configuration:mta:postfix subpages (look at the index to
> find them).
>
>> >
>> > What motive the person stating the "one process/mail" thing has, I
>> > surely can't speculate about... But it isn't correct. That much is for
>> > certain.
>> Can't say, lost the url... but if one process can handle multiple mails
>> in the same run, it sounds great.
> Yep. It *is* great;-)
> With MS, you can build the best darned email scanning system you can
> imagine, and in some cases.... youu couldn't even imagine how good
> it'd be:-)
>
> Cheers

Jules

- -- 
Julian Field MEng CITP
www.MailScanner.info
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