Tornado comes with limited support for WSGI. However, since WSGI does not support non-blocking requests, you cannot use any of the asynchronous/non-blocking features of Tornado in your application if you choose to use WSGI instead of Tornado's HTTP server. Some of the features that are not available in WSGI applications: @tornado.web.asynchronous, the httpclient module, and the auth module.
in other words: WSGI sucks
Running Vhosts Under Separate UIDs/GIDs With Apache2 mpm-peruser On Debian Etch | HowtoForge - Linux Howtos and Tutorialsby camel & 1 other (via)
How To Set Up A Loadbalanced High-Availability Apache Cluster Based On Ubuntu 8.04 LTS | HowtoForge - Linux Howtos and Tutorialsby camel
This HOWTO describes a web server written for the day when even Yaws is not quick enough.
After some recent optimizations, the Dojo Cometd implementation of the Bayeux protocol running on the Jetty web server can now handle up to 20,000 simultaneous users per server while maintaining sub-second latency.
impressive numbers. Does the Twisted one can beat that?