Scalable (incoming) mail cluster
This is one way to build a scalable mail infrastructure. Besides
GlusterFS, the performance is pretty good.
"Business Case" for this setup:
- Postfix, because it is written by a Dutchman and it supports the Proxy Protocol. Proxy protocol will preserve the original IP address and forward that to the back-end. The original IP address is needed for DNS-based blacklisting of spammers.
- HAProxy, because it supports/invented the Proxy Protocol
- GlusterFS, because it is a cool way to experiment with a clustered file-system and easy to setup
- Lighttpd, because it is not Apache
- OpenLDAP and Bind are just de facto standard applications