Forum OpenACS Q&A: Hi, I have located a hosting company that might be able to host openacs...
The quantact hosting provides you with VPS (virtual private server) , it's like having a linux box of your own , you can install,run any thing on it, so it's possible to install openACS on it and there are lot of hosting providers offering vps .
Also sometimes these small companies are many levels of reseller away from the network providers, and their uptime and network speed are not always very good.
If you're up for being your own sys admin, and don't need commercial quality uptime, these places will work fine.
In Xen, you cannot over-commit RAM, so if you pay for a 256MB VPS, they cannot hide whether or not you actually have 256MB dedicated to you. And 256MB if not 512MB is the bare minimum I would recommend for OpenACS or .LRN if you have any kind of traffic.
In Virtuozzo, the resources are usually shared and over-committed or over-subscribed, however, Virtuozzo has a good reputation amongst hosters, provided that the company running the server knows what they are doing and set limits properly. Also the filesystem cache is not part of your RAM allocation as I understand it, since the filesystem is cached globally by the host kernel.
I have found that Solaris Zones (part of Solaris 10) are superior to Xen in terms of CPU performance and ease of use, and superior to Virtuozzo in terms of quick setup, maintainability and price (especially since Solaris 10 is free). Also Solaris' virtual memory manager appears to perform better than Linux, however, with all the changes in 2.6.x that may no longer be the case. However, aside from Zill.net (my company), virtually no one offers Solaris as a shared server solution.