Just found this very good article about optimizing servers.
ulimit
Nginx and worker_connections are more than open file resource limit warning
If you encounter this warning message under Linux: 2009/03/09 21:23:19 [warn] 26827#0: 4096 worker_connections are more than open file resource limit: 1024 A solution is to use the command ulimit in nginx start script, just before lunching nginx: […] ulimit -n 65536 […]