Linux swapfile with systemd

Preliminary notes:

• This is a short transcript of the steps necessary to add a swapfile under linux. For a more detailed explanation I refer to the ArchWiki page.
• Unlike the most other tutorials for swapfiles you will find in the internet that add the swapfile to fstab, we will create a swapfile.swap systemd unit.
• This tutorial assumes that you have a working zram swap device with priority 100.

Create the swapfile

mkswap --check -U clear --size 4G --file /swapfile

Create a systemd swap unit for it

systemctl edit --full --force swapfile.swap
systemctl enable --now swapfile.swap

[Unit]
Description=Disk Swap on /swapfile

[Swap]
What=/swapfile
Priority=50
Options=discard

[Install]
WantedBy=swap.target