See also : https://www.linode.com/docs/web-servers/apache-tips-and-tricks/tuning-your-apache-server/
curl -sL https://raw.githubusercontent.com/richardforth/apache2buddy/master/apache2buddy.pl > apache2buddy.pl
perl apache2buddy.pl –skip-os-version-check
vi /etc/apache2/mods-enabled/mpm_prefork.conf service apache2 restart