Add Swap to CentOS

For Centos 6

See what size swap is

[[email protected]]# free -m

or

[[email protected]]# swapon -s

Create directory

[[email protected]]# mkdir /home/swap

Create a swap file

[[email protected]]# fallocate -l 12G /home/swap/swap.img

Checking

[[email protected]]# ls -alh /home/swap/swap.img

Assigning rights

[[email protected]]# chmod 600 /home/swap/swap.img

Create swap space

[[email protected]]# mkswap /home/swap/swap.img

Turn on the swap file

[[email protected]]# swapon /home/swap/swap.img

Checking

[[email protected]]# swapon -s

Adding the swap file to startup

[[email protected]]# nano /etc/fstab
/home/swap/swap.img swap swap defaults 0 0

To turn off this swap file

[[email protected]]# swapoff /home/captain/swap/swap.img

Checking

[[email protected]]# swapon -s

For Centos 7

See what size swap is

[[email protected]]# free -m

or

[[email protected]]# swapon -s

Create a 12 Gb file

[[email protected]]# dd if=/dev/zero of=/swapfile bs=1M count=12288

Create swap space

[[email protected]]# mkswap /swapfile

Assigning rights

[[email protected]]# chmod 600 /swapfile

Turn on the swap file

[[email protected]]# swapon /swapfile

Adding the swap file to startup

[[email protected]]# nano /etc/fstab
/swapfile swap swap defaults 0 0

To turn off this swap file

[[email protected]]# swapoff /swapfile

Checking

[[email protected]]# swapon -s