Apache2

• http://www.tecmint.com/apache-performance-tuning/
• https://wiki.mikejung.biz/Apache
• https://elias.praciano.com/2015/12/como-configurar-o-modulo-mpm-prefork-para-melhorar-a-performance-do-servidor-web-apache/
• http://stackoverflow.com/questions/18761239/apache-server-reached-maxclients-setting-consider-raising-the-maxclients-settin
• http://www.rodrigocalado.com.br/implementando-o-tuning-no-apache-2-4-x-prefork-mpm-sistemas-ubuntu-centos-amazon-linux-etc/

lista os módulos apache2ctl -M