Cyrus Murder or IMAP proxy.

[Michael Alan Dorman]

On Mon, 28 Jul 2008 08:14:21 -0500 (CDT)
"Chris St. Pierre" <stpierre at NebrWesleyan.edu> wrote:

> On Mon, 28 Jul 2008, UnlimitedMail.net - Carles Xavier Munyoz Bald__ wrote:
> > What I'm losing if I use an IMAP proxy instead of Cyrus Murder?

You are losing a bunch of technologies intended to make creating a
distributed and/or fault-tolerant mail system simpler and easier to set
up.

The biggies, from my perspective, are replication and host transparency.

Replication is pretty obvious, at least with respect to fault-tolerance
using shared-nothing hardware.

By host transparency, I mean you're going to have to handle proxying
not just IMAP, but you'll also need to direct your SMTP server so
incoming messages get delivered to the right host.  And you'll need to
proxy POP if you're going to offer that.

Most of those are solved problems---nginx can handle them, though
you'll need to hack up an auth daemon.  Takes a few hundred lines of
Perl+POE to do, or, I imagine, Python+Twisted or whatever you prefer.

If you're going to provide access to sieve scripts, you're going
to have to figure out some way to proxy that, as nginx _doesn't_ do
that.

So on and so forth.  It's not that you can't do it, but you're going to
have additional software to handle all the things that Murder is
intended to handle.

> Unless you have a serious need for mailbox sharing, Murder isn't worth
> it, IMHO.  It takes a LOT of hardware to be really fault-tolerant, and
> has all of the other caveats you posted.

If you are running more than one server, whether for fault-tolerance or
scalability, I think a non-Murder config is going to have a higher cost
overall, as it is going to involve more software to learn, configure,
monitor and run, while having basically the same hardware requirements.

> Perdition is the IMAP proxy usually used for this application.

Err, I think people with high-volume requirements have mostly moved to
nginx, which is much lighter-weight than perdition.

Mike.