Ubuntu Swap Cheatsheet

Good article on why swap is important: https://chrisdown.name/2018/01/02/in-defence-of-swap.html

• swapon -s
  • show swap info
• swapoff -a
  • turn off all swap devices
• swapon -a
  • turn on all swap devices

Swappiness

• cat /proc/sys/vm/swappiness

  • 60 = default, use swap when ~ half of ram is used

  • 10 = use swap when only 10% ram free

  • 0 = use swap only when absolutely necessary

• sudo vi /etc/sysctl.conf

  • # Reduce swappiness
    vm.swappiness = 10

• sudo sysctl vm.swappiness=10

Create Swapfile

• sudo fallocate -l 4G /swapfile

• sudo chmod 600 /swapfile

• sudo mkswap /swapfile

• sudo swapon /swapfile

• sudo vi /etc/fstab

  • /swapfile swap swap defaults 0 0

• sudo swapon --show