====== How to add Linux Swap file if you don’t have Swap Partition ======
[[http://blog.mypapit.net/2007/07/how-to-add-linux-swap-file-if-you-dont-have-swap-partition.html|VIA]]

Assuming you want to put it in '/', create an empty 1024MB file:
  dd if=/dev/zero of=/swap bs=2048k count=512

Format it as a swap file:
  sudo mkswap /swap

Add it to your running Linux system:
  swapon /swap

Add /swap to fstab for automatic swap activation:
  echo "/swap none swap sw 0 0" >>/etc/fstab

Verify that you've added the newly created swap to your Linux based operating system:
  free -m