How To Create a Linux Swap File

linux

sudo dd if=/dev/zero of=/swapfile bs=2048 count=1048576

mkswap /swapfile

swapon /swapfile

in /etc/fstab aggiungere in fondo:
/swapfile none swap sw 0 0

echo 10 | sudo tee /proc/sys/vm/swappiness
echo vm.swappiness = 10 | sudo tee -a /etc/sysctl.conf

chown root:root /swapfile
chmod 0600 /swapfile

source:
https://www.digitalocean.com/community/tutorials/how-to-add-swap-on-ubuntu-12-04
http://ericeastwood.com/blog/14/swap-file-guide-ubuntu
http://www.rackspace.com/knowledge_center/article/create-a-linux-swap-file
http://makandracards.com/makandra/17253-create-swap-space-on-linux