$ sudo dd if=/dev/zero of=/swapfile bs=1M count=20480
$ sudo dd if=/dev/zero of=/swapfile bs=1M count=10240
$ sudo chmod 600 /swapfile
$ sudo mkswap /swapfile
$ sudo file /swapfile
$ sudo swapon /swapfile
$ sudo vi /etc/fstab
/swapfile swap swap defaults 0 0
$ sudo swapoff /swapfile
$ sudo swapon -s
$ sudo swapon -a
$ sudo swapon -s
Filename Type Size Used Priority
/swapfile file 5242876 0 -2