On Dec 23, 2009, at 1:12 PM, Derrick Wooden wrote:

> I'm well aware that SMTP doesn't mean instant.

Regretfully, you are the exception.  Most people don't seem to get this concept 
-- even people like my wife, and I've been trying to pound this one into her 
brain for ten years.

> I'm just looking at a solution that can cut 1E6 emails being delivered in 12
> hours down to say 4 hours.  With a fast server, correct MTA optimization and
> proper Mailman setup could this be attainable?

I believe so, yes.  However, optimization would have to be done at all levels, 
not just the MTA.

If you've got that many recipients, then you're probably seeing a lot of Python 
pickle contention during initial list delivery, and you'd want to break that 
down into a number of sub-lists.  If you have a million recipients, then a 
thousand sublists with a thousand subscribers each would probably be overkill, 
but a hundred sublists with ten thousand subscribers each probably would not be 
enough.

Using postfix, you can tune things for maximum parallelization, and eliminate 
things like unnecessary DNS queries and blacklist checks on outbound (because 
you've already done them on inbound, or it's an announce-only list and they 
don't need to be done at all).  You can also tune things so that any messages 
which don't get delivered right away can get pushed off onto another "slow 
delivery" server, thus keeping the primary server pumping as fast as possible.  
For an announce-only list, you might also want to consider putting the primary 
mail queues on solid-state disk -- you shouldn't need a particularly large SSD 
for the primary server if the "slow delivery" server has sufficient storage.

Your primary bottlenecks are going to be disk latency and locking contention.  
If you can eliminate or minimize those, everything else should flow as fast as 
your Internet connection allows.

> The Barack Obama email campaign used Postfix for their MTA and PHP Mailer to
> deliver their newsletters.  

How many people did they deliver to?  How many machines did they have doing 
delivery?  How often did they send out messages?  How large were those 
messages?  Did they do DKIM signing on each message?  There's lots of variables 
here that could affect their numbers relative to what you might be able to 
achieve.

> I'm using a package install of Mailman along with Exim through cPanel.  I
> now know that this setup is not optimal and needs lots of tweaking.  I'm
> looking into VERP also based on helpful information in the FAQs.

I've done the best I can to encode as much of my knowledge as possible into the 
FAQs.  Pretty much everything is there, or I point to references where the rest 
of the information can be found.  The key is knowing what you're looking for 
and when you've found it.

--
Brad Knowles <bradknow...@shub-internet.org>
LinkedIn Profile: <http://tinyurl.com/y8kpxu>

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