How To Add Swap on Ubuntu 12.04
To add a swap-partition instead of swap-file:
blkid /dev/sdax (get UUID)
mkswap /dev/sdax (format swap partition)
swapon -U xxx
nano /etc/fstab (edit fstab) UUID=xxx none swap sw 0 0 (enter and save this text to make swap permanant) (then close fsantab)
To add a swap-file
https://www.digitalocean.com/community/articles/how-to-add-swap-on-ubuntu-12-04