This documentation is for Dovecot v2.x, see wiki1 for v1.x documentation.

big enterprise mail system for about 35,000 users


inbound IMAP/SMTP

2 IBM x306m with Xeon 3.2, 512MB RAM

outbound SMTP

2 IBM x306m with Xeon 3.2, 512MB RAM

IMAP director/balancer

2 IBM Blades with Xeon 3.2, 2GB RAM

IMAP backend

4 IBM Blades with 2 Xeon 3.2, 4GB RAM


2 IBM Blades with Xeon 3.2, 2GB RAM


2 IBM Blades with Xeon 3.2, 2GB RAM


3 IBM Blades with 2 Core2Duo Xeons 1.6, 4GB RAM

OS: customized Debian sarge with Kernel 2.6.16-smp


MasterUser for webmail authentication, custom PasswordDatabase/CheckPassword to authenticate against a SOAP-service.


The backend servers each use two 350GB LUNs on a IBM DS8300 storage giving us 2.8TB of mail storage. The director runs dovecot as proxy to balance the load over the four backend servers. Each LUN has its own virtual IP for scalability to up to eight servers. The proxy uses a PostgreSQL database to find the backend-IP to a given user.

mail delivery

The director runs qmail for mail transfer with a custom MDA that reads filtering rules from the database. Rules include text matching of arbitrary headers and mail bodies and allow ignoring mails, delivering mails to IMAP folder and forwarding mails. Delivery to mailboxes works over IMAP to the backend servers. Users can edit the filtering rules via webmail or the webservice.

webservice, webmail

Webmail is a highly customized Horde/IMP installation (Apache 2.2, PHP 4.4). The webservice is Java webapp using XFire to export SAOP services for reading and sending mails, managing mailboxes, filters etc.

None: DovecotServerInstallations/DebianUbuntu/35kUsers (last edited 2009-03-15 22:35:23 by localhost)