Moodle Clusters
From MoodleDocs
A Moodle cluster, in this sense, is a collection of computers that may or may not mirror a Moodle, but will load share. A lot of people could benefit if they understood how this could be done.
You might want to start here. Linux HA is a project dedicated to developing Linux Clusters.
This initially appears to be the same thing, but then reading it, The Linux Virtual Server project is very different.
Not everybody uses Linux though, For Windows Server 2003, the concept of Web Farming seems to be growing.
And from Microsoft itself, comes this article on Setting Load Balancing Parameters, also in Server 2003.
