I thought that some of you would find this of interest. Here is a snap shot of the statistics page from one of our Moodle Servers.
Moodle is running on a DELL 2950 server as a VM-Ware virtual machine allocated 4 processors and 12 GB of memory using RH-5. There are 2 other VM-Ware Virtual machines running at the same time on the host hardware. Database (MySql) is running on a separate dedicated server.
The system was tuned, stress tested and tuned some more.
The system was tuned and tested to comfortably support 1200 heavy concurrent users.