Creating swap partition in CentOS 7

We should firstly examine the current swap space with:

swapon -s

Identify how much space we have available for swap with:

df -h

and use the fallocate command to quickly create our swap file e.g.:

sudo fallocate -l 128m /swpfile

Set the relevent permissions on the swap file (we don't want anyone else except root to have access to the swap file!):

sudo chmod 600 /swpfile

And then instruct the system to create the swap space with:

sudo mkswap /swpfile

and enable the swap space with:

sudo swapon /swpfile

and then confirm with:

swapon -s

and

freemem