[ On Wed, February 4, 1998 at 20:48:09 (-0800), Tom wrote: ]
> Subject: Re: [EXIM] Maximum Message Size
>
> Well, there are some people who have problems. But the majority of
> users that I surveyed like the 10MB limit, and can handle it.
You're talking to admins, not users. What admins say is often
irrelevant when considering the user's concerns.
> > to implement them for the user would require that everyone avoid POP and
> > use only IMAP or something similar where control over the spool file can
> > be had without first downloading it.
>
> I don't understand the relevance. If you want to have user controls,
> you want to control the amount of e-mail going into a box, not how users
> get it out?
Again you've missed the point. The relevance of large message limits is
particularly accute for the end user, *NOT* the admin. I realize that
though the admin should have his user's interests in mind, many face
conflicting goals and other constraints on their ability to make
decisions that favour the lowest common denominator instead of decisions
that favour those who yell the loudest and have the deepest pockets.
If big mail messages go into a server then the users have to have some
way to get them back out again. Refusing them up front may not be so
friendly in all cases, but it's one heck of a lot better than making it
trivial for anyone in the world to get a user into the position where
they are not able to even begin downloading their new mail.
> > [[You should see what 8,000 POP users over over high speed links can do
> > to a large and well endowed Sparc-Ultra when they all hit the POP server
> > every 5-60 seconds, esp. when those users inevitably learn to keep large
> ...
>
> You should get a real server, or you should use Exim :)
What exactly does Exim (or any other MTA) have to do with providing POP
service? Since when is a "well endowed Sparc Ultra" not a real server?
Of course that same machine should be able to handle at least 40-50
times as many users with similar connect rates if it were running Cyrus
IMAP (which I think it is now -- yes, it is, and now I get a POP server
prompt in a mere moment instead of up to 20 seconds).
> Users coming over slow connections are worse, because more are in
> progress are any one time. A client system that I manage handles 15,000
> POP and IMAP users, each with a 10MB limit, accepting about 900MB to
> 1000MB of new mail per day. It receives over 60,000 POP/IMAP logins per
> day. Load average is about 0.60 during heaviest load.
You're obviously running something decent like Cyrus IMAP too then....
However 60,000 POP/IMAP logins for that many users is only a fraction of
what I was refering to. Consider what your server would do if it were
running an old-fashioned POP server and were servicing somewhere between
200,000 and 650,000 POP/IMAP connections per day (Netscape running with
10min. interval checks for 24hours per day per user). Even with Cyrus
that could easily mean a load average of up to 6.0 on your server, and
probably a lot more unless you could endow it with enough memory and
fast enough disks.
> Again, this is resposibility of that site. If it really important, they
> can setup an outside relay to protect fragile internal mail systems.
Of course, but in real life many don't. Many refuse to believe in the
first place that their internal mail systems are fragile.
> Well, when I sent this message, your mail server was unreachable,
> so I wasn't even sure if you'd get this message :)
My mail server? I have a secondary MX server that's usually available
even if my crotchety old system has crashed or my line has been downed.
Surely you use a mailer that knows how to deliver to a secondary MX
host, no? Or was there network trouble between here and there, but for
some strange reason not to the UK?
> Also, planix.com (your employer?) has a 2MB limit. What's the deal with
> that? :)
"I'm not just the president, I'm a customer!" -- well strictly speaking
I am not the president, but it is in effect a partnership. In a sense I
am also a customer though in that my own Internet connection goes via
the Planix hub.
I'm sorta surprised that we have a 2MB limit -- I'd kinda expected 1MB
at the most, but I don't really care about that one as my own mailer has
just a 100KB limit (and I don't even have to download mail from my own
server!).
--
Greg A. Woods
+1 416 443-1734 VE3TCP <gwoods@???> <robohack!woods>
Planix, Inc. <woods@???>; Secrets of the Weird <woods@???>
--
*** Exim information can be found at
http://www.exim.org/ ***
