With the release of the Raspberry Pi4 8gb version, and SSD booting, this could be still useful for anything below 8gb of ram.
Git clone log2ram repo
git clone https://github.com/azlux/log2ram.git
go into folder and run install.sh
cd log2ram
sudo ./install.sh
Modify the amount of ram to use. 40M is stock and another place says try 128M, up to you.
sudo nano /etc/log2ram.conf
Reboot the PI
sudo reboot
Check the log2ram changes were persistent.
df -h
That was an easy tweak.