prereq

apt install bc -y

swap-ext

#!/bin/bash

# Scripts creates additional swap space in file /extraN.swap

function addSWAP4GB {
    # $1 = ID
    test -e /extra${1}.swap || {
        sudo dd if=/dev/zero of=/extra${1}.swap bs=1024 count=`echo '1024*4*1000'|bc`
        sudo mkswap /extra${1}.swap `echo '1024*4*1000'|bc`
    }
    sudo swapon -p $1 /extra${1}.swap
}

addSWAP4GB 0
addSWAP4GB 1
addSWAP4GB 2
addSWAP4GB 3

stats

sudo swapon -s
sudo free -m