Before begin, please check if the system already has swap space available. Even though it’s possible to have multiple swap files or swap partitions, one should be enough.

free -h

Output
total used free shared buff/cache available
Mem: 488M 36M 104M 652K 348M 426M
Swap: 0B 0B 0B

As we can see no swap is active on the system. We will create a 1 Gigabyte file in this guide. Adjust this to meet the needs of your own server:

fallocate -l 1G /swapfile
chmod 600 /swapfile
mkswap /swapfile
swapon /swapfile

We can check the output of the “free” command again to verify the swap:

free -h

Output
total used free shared buff/cache available
Mem: 488M 37M 96M 652K 354M 425M
Swap: 1.0G 0B 1.0G

The swap space has been set up successfully and our operating system will begin to use it.

Now let’s make the swap space used permanently:

cp /etc/fstab /etc/fstab.bak
echo '/swapfile none swap sw 0 0' | sudo tee -a /etc/fstab

Done!