[CentOS] Large scale Postfix/Cyrus email system for 100,000+ users

Les Mikesell lesmikesell at gmail.com
Wed Oct 24 13:00:33 UTC 2007

Matt Shields wrote:
> I'm trying to set up a large scale email system that supports 100,000+
> IMAP accounts.  We have an existing frontend web interface that does a
> lookup on a mysql db to figure out which IMAP server to connect to for
> each user.  For the email infrastructure we have decided on Postfix
> and Cyrus.  We have configured both to use mysql to get the virtual
> user information.
> Because of the way that the infrastructure is (biz reasons) we are not
> doing shared storage, we have numerous IMAP servers that we distribute
> accounts across.  As we add more users, we image up a new IMAP server.
>  For our business's scaling purposes this was the best plan.
> What I am having a problem is how do I get postfix to transfer the
> email to the particular IMAP server that the user account is on.  I
> know that I need to use lmtp and transport, but all the examples I
> have seen show forwarding all email to 1 IMAP server.  I would like
> Postfix to do a lookup for each mailbox and determine which IMAP
> server to deliver it to.

I thought the usual ways of doing this were to either use a 
high-performance NFS server (netapp filer...) and maildir format so you 
can run imap from any client facing server, or to keep the delivery host 
information in an LDAP attribute that you find when validating the address.

   Les Mikesell
    lesmikesell at gmail.com

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