Well, there are a few ways to do AOLServer/OpenACS that I have stumbled across.
First, you can start a separate instance for each OpenACS installation, using 1 IP per installation. For this, if you are using daemontools, you can just specify the initial tcl script for each instance.
Second, you can do the above, but use multiple ports on the same IP -- still having separate instances. Then, you use Pound, http://www.apsis.ch/pound/ This is the method that Bart Teeuwisse advocates.
https://openacs.org/forums/message-view?message_id=169655
Or, you can run multiple instances using multiple ports, and use a slick little fix by Jade Rubick.
http://www.rubick.com:8002/openacs/easy_virtual_hosting
Or, you can use the virtual hosting built into AOLServer
http://www.panoptic.com/wiki/aolserver/98
also referenced
https://openacs.org/forums/message-view?message_id=189026
There are benefits and pitfalls to each method. Currently I run a separate instance for two OpenACS installations that each have their own IP. Then, I have five OpenACS instances running under one AOLServer instance on a 512mb machine and might consider pushing it too six OpenACS instances which I think is about the maximum practical limit for low-volume personal sites.
