Some time your VPS provider wont create swap by default when they launch a new VPS for you. Swap play important role in cache process.

And technically its a good practice to have swap specially in cases where the RAM is low, small VPS servers for example. Lets get started.

Note: 4G = 4GB(size of the swap), change it to your desired number. If you are already root, remove sudo. swapfile is the name.

sudo fallocate -l 4G /swapfile

Verify:

ls -lh /swapfile

Give it appropriate permissions:

sudo chmod 600 /swapfile

Now lets create swap:

sudo mkswap /swapfile

Enable swap on swapfile:

sudo swapon /swapfile

Verify that swap is on:

swapon -s
free -m

swap <>

To enable it on each boot, add it to fstab:

sudo vim /etc/fstab

/swapfile swap swap sw 0 0

Below are extra helpful steps which will make the things more smoother:

sudo vim /etc/sysctl.conf

Add the following lines at the end:

vm.swappiness = 10
vm.vfs_cache_pressure = 50