Recently we purchased several Sun Fire X4100 servers (each one of them have 4GB of ram), and we are testing them right now. Here is the config:
1 Loadbalancer
2 AppServer
1 Database Server
1 Admin and backup server
On top of my to-do list is to test the load balancing between these servers, and most importantly, to make sure if we have 2-3 classes (each class has say, 50 students) having chat sessions at the same time, the server(s) could still handle the load. I have been talking to the ixiacom.com to test drive their ixLoad product (see: http://www.ixiacom.com/products/performance_applications/pa_display.php?skey=pa_ixload) to see if this could fit with our needs, but at the same time, would like to check with the moodle community to see if there is any other easier way to test out (simulate 200+ concurrent users chatting on Moodle site, in 20+ different chat rooms) the moodle chat application. Bottom line is that we need to know to what extent our new server(s) could handle concurrent chat users (e.g. support up to how many concurrent users before the system start to dramatically slowing down, how well the chat app could scale among different servers..etc.). Any suggestion about how to tackle this issue?? Many thanks!