Instructions found from DigitalOcean Tutorial
Create and Enable the Swap File
Now it’s time to create the swap file itself using the dd command :
sudo dd if=/dev/zero of=/swapfile bs=1024 count=512k
“of=/swapfile” designates the file’s name. In this case the name is swapfile.
Subsequently we are going to prepare the swap file by creating a linux swap area:
sudo mkswap /swapfile
The results display:
Setting up swapspace version 1, size = 536866 kB
Finish up by activating the swap file:
sudo swapon /swapfile
You will then be able to see the new swap file when you view the swap summary.
Filename Type Size Used Priority
/swapfile file 524280 0 -1
This file will last on the server until the machine reboots. You can ensure that the swap is permanent by adding it to the fstab file.
Open up the file:
sudo nano /etc/fstab
Paste in the following line:
/swapfile swap swap defaults 0 0