vm:~# mkswap file
Setting up swapspace version 1, size = 3145723 kB
no label, UUID=d42e1c05-8699-436c-afa1-c15cfdefa0bd
vm:~# swapon file
free -m
vm:~# free -m
             total       used       free     shared    buffers     cached
Mem:          2027       1977         50          0          3       1776
-/+ buffers/cache:        196       1831
Swap:         3956         42       3914
vm:~#