https://ubuntu.com/tutorials/configure-ssh-2fa

====== get current swap size ======
du --apparent-size --block-size=1 /var/swap.img -h

====== create 8GB swap ======
swapoff /var/swap.img dd if=/dev/zero of=/var/swap.img bs=1024k count=8000 mkswap /var/swap.img swapon /var/swap.img 

https://github.com/netdata/netdata/issues/1076#issuecomment-509214247

Tail log:

journalctl -xefu service-name

https://caprover.com/docs/disk-cleanup.html

ncdu --exclude /var/lib/docker/overlay2

Press d to delete selected

sudo apt-get autoclean to clean up outdated package deb files

sudo apt-get autoremove to remove any unused dependencies

sudo apt-get clean to clean up apt cache

/etc/systemd/journald.conf

SystemMaxUse=100M, SystemMaxUse=1G etc

sudo service systemd-journald restart then applies changes and vacuums