Create swap file on a running Linux machine
Solution 1:
Assuming that you want to create 512MB swap file:
# dd if=/dev/zero of=/swapfile bs=1024 count=524288
Setup swap area with:
# mkswap /swapfile
Activate it:
# swapon /swapfile
Add to /etc/fstab for permanent:
echo -e "/swapfile\t\tswap\t\tswap\t\tdefaults\t0 0" >> /etc/fstab
and verify with free -m.