Generally, the size of the swap file depends on how much RAM your system has:

• Less than 2 GB RAM – 2 times the amount of RAM.
• 2 to 8 GB RAM – the same size as the amount of RAM.
• More than 8 GB RAM – at least 4 GB of Swap.

Only root or user with sudo privileges can activate the swap file.

1). First, create a file that will be used as swap:

sudo fallocate -l 2G /swapfile

2). Set the file permissions to 600 to prevent regular users to write and read the file:

sudo chmod 600 /swapfile

3. Create a Linux swap area on the file:

sudo mkswap /swapfile

4). Activate the swap file by running the following command:

sudo swapon /swapfile

5). To make the change permanent open the /etc/fstab file:

sudo vi /etc/fstab

and paste the following line:

/swapfile swap swap defaults 0 0

6). Verify that the swap is active by using either the swapon or the free command, as shown below:

sudo swapon --show

and

sudo free -h

Adjusting the Swappiness Value

On Ubuntu, the default swappiness value is set to 60. You can check the current value by typing the following command:

cat /proc/sys/vm/swappiness

While the swappiness value of 60 is OK for most Linux systems, for production servers, you may need to set a lower value.

sudo sysctl vm.swappiness=10

To make this parameter persistent across reboots, append the following line to the /etc/sysctl.conf file:

vm.swappiness=10

Removing a Swap File

To deactivate and delete the swap file, follow these steps:

1). First, deactivate the swap space:

sudo swapoff -v /swapfile

2). Next, remove the swap file entry from the /etc/fstab file.

/swapfile swap swap defaults 0 0

3). Finally, remove the actual swapfile file using the rm command:

sudo rm /swapfile