[Mailman-Developers] Huge lists

J C Lawrence claw@cp.net
Thu, 25 May 2000 19:52:09 -0700

On Thu, 25 May 2000 10:32:41 +0100 
Nigel Metheringham <Nigel.Metheringham@VData.co.uk> wrote:

> Wietse had some figures on MTA performance analysis which he used
> as part of the design process for Postfix.  He concluded that disk
> I/O was *the* limiting factor for an MTA...

Excellent point.

> If we have a million user list... and a message of a few K, I'm
> not sure I want to have a few GB of queue space taken up.  If some
> idiot sends a 1M attachment I doubt many of us have the TB spool
> space.

FWLIW, this is the reason I specced having the handler process feed
the MTA at a set rate, thus allowing the MTA to attempt to drain the
spool as it comes in.  Without some sort of feedback (perhaps `df`?)
you can't guarantee anything of course, but it *should* help without
getting complex of MTA specific.

> Having said that I *really* would like the possibility of the
> occaisional message (maybe even just the password
> reminders.. although I'd prefer a method where some messages if
> the list was in a state where it has recently seen bounces that it
> cannot tie to a particular subscriber) be sent out using VERP.
> However then we also need to recode the MTA incoming handling to
> take that - aliases don't cut it any more.

Not exactly.

I did exactly this for one of my list servers, tho not exactly in
the VERP style.  What I did was to to have every N'th message
broadcast be pseudo-VERPed.  I did this by encoding special
subscriber-specific headers into the subscriber-individual messages,
and then looking for those headers in bounces (I haven't found a
single MTA whoses bounces don't at least quote the original
message's headers).  Spot the special headers, flag the relevant
account, and so forth.  Very clean.  Very effective.  Almost all the
benfits of VERP without the pain (I don't consider the
per-subscriber subscribe/unsubscribe addressing etc interesting).

> chuqui@plaidworks.com said:
>> There are exchange sites out there who's idea of a bounce message
>> is to return the mail to the "to:" line with only the Message-ID
>> changed. you can imagine how much fun THAT is.


> That particular one you mention should be blocked from the net -
> presumably their upstream is clueless too.

I noticed a while back that my Exim reject logs were full of entries
for a system called "<something>_mail" (forget what "Something"
was).  Underscores are of course not welcome for HELOs, so Exim was
rejecting the traffic.

To cut to the chase, it turned out to be an Exchange box at a
company that was trying to get me to do some consulting for them,
and who were very upset that I wasn't replying to their email.
Further, it turned out, or so they said, that the MS manual for
Exchange strongly recommended that they name the box

Sometimes I wish more Exchange sites would read and follow their

J C Lawrence                              Internet: claw@kanga.nu
----------(*)                            Internet: coder@kanga.nu
...Honorary Member of Clan McFud -- Teamer's Avenging Monolith...