sudo apt-get update
sudo apt-get upgrade
sudo swapon -s
free -m
sudo swapon -s
df -h
sudo fallocate -l 4G /swapfile
ls -lh /swapfile
sudo chmod 600 /swapfile
ls -lh /swapfile
sudo mkswap /swapfile
sudo swapon /swapfile
sudo swapon -s
free -m
sudo nano /etc/fstab
cat /proc/sys/vm/swappiness
sudo sysctl vm.swappiness=10
sudo sysctl vm.vfs_cache_pressure=50
sudo nano /etc/sysctl.conf
https://www.digitalocean.com/community/tutorials/how-to-add-swap-on-ubuntu-14-04