How to config SWAP in Linux (CentOS, Ubuntu,..)
Step 1
set 1024mb (bs=1024k)
cd /var touch swap.img chmod 600 swap.img dd if=/dev/zero of=/var/swap.img bs=1024k count=1000
Step 2
mkswap /var/swap.img
Complete
swapon /var/swap.img
Check swap memory
free -m