increase swap file size to 8Gb

ubuntu-make-swap-file.sh

# ref. https://askubuntu.com/a/1075516/22308

sudo swapoff /swapfile # make all swap off
sudo rm -rf /swapfile # remove the current

#                                    8*1024Mb=8192Mb
#                                    4*1024Mb=4096Mb
sudo dd if=/dev/zero of=/swapfile bs=1M count=4096 # resize the swapfile to 8Gb
sudo chmod 600 /swapfile

sudo mkswap /swapfile # format the file as swap

sudo swapon /swapfile # activate it
sudo swapon -s        # view swap size