swap
List active swap areas
# procfs
cat /proc/swaps
# cli tool
swapon --show
Manual swapfile setup
# One time:
# Create and initialize swapfile.
# mkswap will initialize swap area over full filesize by default.
sudo dd if=/dev/zero of=/swapfile bs=1G count=1
mkswap /swapfile
# Enable swap file (until next reboot).
swapon /swapfile
# Persistent setup of swap file.
echo "/swapfile none swap sw 0 0" | sudo tee -a /etc/fstab
# Disable swap file (until next reboot).
swapoff /swapfile
Recommended file permissions
0600
and file owneruid=0 (root)
.
Using dphys-swapfile
service.
Dynamically computes size of swap file based on installed RAM.
# Setup and enable swap based on /etc/dphys-swapfile.
dphys-swapfile setup
dphys-swapfile swapon
# Disable swap on configured file.
dphys-swapfile swapoff
Usually comes with a script to be automatically run at system startup and shutdown. For example as
systemd
service:systemctl status dphys-swapfile