Creating a Swapfile

Creating a swapfile can be easily done with dd.

$ sudo dd if=/dev/zero of=/swapfile bs=1M count=4k

This will create a 4GB file directly under the / (root) directory.
Hint: count specifies how many 1M (bs) blocks will be allocated.

After the creation make sure to alter the permissions of the created file.

$ sudo chmod 600 /swapfile

Now follows the actual formatting of the given file.

$ sudo mkswap -U clear /swapfile

Activate the swapfile after formatting.

$ sudo swapon /swapfile

The only thing left to do is to mount the swapfile on every boot. To do this we will add the following to the systems fstab file (/etc/fstab).

$ sudo vim /etc/fstab

Append the following to your fstab file:

/swapfile none swap defaults 0 0

Done, the next time the system boots the swapfile will automatically be used.

Further reading: https://wiki.archlinux.org/title/swap