[Gllug] OT: Web based email

[Mike Brodbelt]

Walid wrote:
> 
> Look at imp/ or sqwebmail; there were a recent package in freshmeat that do all
> the hardwork for you!
> But mind you; it only uses the best MTA :) qmail

Hmm - I've used IMP, and it has no requirements for qmail at all. It's
also horrible, IMHO, and has had several security holes recently.

You could use squirrelmail, its a pretty good IMAP webmail client. For
the size installation you're considering though, your MTA/store is going
to be much more important. I'm using sendmail/Cyrus IMAP in a couple of
places, and that can probably keep up if you give it the hardware.

Cyrus implements a single instance store - a mail sent to 100 people on
your server will be stored once, and hard linked to for the remaining
users. This may well be a big win in your situation, depending on the
usage pattern of your users. Run the store on a fast filesystem that can
deal well with lots of small files (Reiser?), as disk I/O will be your
bottleneck.
Cyrus also frees you from the requirement that each user have an account
in /etc/passwd, supports a partitioned mail store, and several other
things that may well be desirable.

For your MTA, it should preferably touch the disk as little as possible,
and talk to the store as directly as possible. If you use a Cyrus
backend, you can deliver via LMTP over a Unix socket. This can be done
with the Cyrus deliver binary, but that would involve forking a process
for each mail delivered, which at 100Gb a day may be a significant load.
Better to use an MTA which can talk LMTP directly. Sendmail will do
this, and I think postfix will also cope. Qmail won't, AFAIK, and I'm
not sure about Exim.

On the commercial side, Sendmail Inc. do products that'll do what you
want, and Messaging direct have some good stuff. I've heard that a tuned
installation of the messaging direct switch and store could achieve 30
messages/second to disk.

HTH,

Mike.

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