Kernel tuning for dedicated linux server.
For kernel >= 4.09
Place file 60-sysctl.conf in /etc/sysctl.d/60-sysctl.conf
and run "sysctl --system"
curl -L https://github.com/khon-kaen-university/server-sysctl/raw/master/60-sysctl.conf > /etc/sysctl.d/60-sysctl.conf && sysctl --system