Re: [Exim] Splitting mail across servers

Im looking at a reliable way of hosting mail for around 250,000 mail
accounts.


----- Original Message -----
From: "randall ehren" <randall@???>
To: "Scott Stavretis" <scott@???>
Sent: Monday, January 28, 2002 2:36 PM
Subject: Re: [Exim] Splitting mail across servers


> > I am after some advise. What is one to do when they have to many users
on a single server (using one domain) and would want to split mail across
multiple servers? What do the larger ISP's do?
>
> how many do you consider "many"? our campus student email server has
> 20,000+ accounts on a single sun 450r and an external a1000 raid. a dual
> or quad intel box and a high performance raid could easily handle the
> same.
>
> > I've been thinking about this and believe the best way to do it would be
based on the first character in the local-part of the e-mail
address/username
> > i.e. mail to a*@??? to j*@??? goes to server 01
k*@??? to z*@domain .com goes to server 01.
>
> seems that most people use ldap to rewrite the address... like this:
>
> a*@??? --> a*@???
> k*@??? --> k*@???
>
> and then you just rewrite the addresses on the outgoing.
>
> > To do this I presume you would need at least three servers 1 being a
forward machine and the other two being physical mail hosts.
>
> sure, one mail hub to receive and send mail, and then the load balanced
> imap/pop servers.
>
> > Obviously I would need a POP3 splitter of some sort, any recommendation
would be good.
> > Then I would need exim to be able to deliver mail based on $local_part
somehow? This is the tricky bit I see.
>
> you could use a file based, database backed, or ldap backed drive to
> direct mail delivery.
>
> -randall
>
>