Very close. From what he later posts about supervisord monitoring - he is basically hitting a server bottleneck of number of threads, which causes him to run o

Very close. From what he later posts about supervisord monitoring - he is basically hitting a server bottleneck of number of threads, which causes him to run out of memory and get into swap space. Then everything goes to hell and he (supervisord) has to restart. Proof: You will have 0 memory free and start using swap when the restart happens - type 'top' and watch this go down. Fix: Use less threads. The number of concurrent users you can support is the # of pages you can serve up per second in each thread times the number of threads your server can handle. So a huge improvement can be caching. Cache pages, blocks, hell maybe your whole site. The cache hits will serve 10-100 times more responses per second than generating your entire page. I consulted on a project that was having horrible server performance on a huge server with relatively static data. The way they produced pages was really poor and took 3 or 4 seconds. There is no way you can serve up a large number of concurrent requests with the turnaround time over a second. I added caching as a quick fix and they ended up just being happy that 99.9% of their pages served up in 1/100th of a second.