Managing swap space is essential for system performance, especially when your system is running low on RAM. Here’s a step-by-step guide on how to manage swap space using common Linux commands:
Check Current Swap Usage

~$ swapon
This command lists all active swap partitions and swap files. It helps you understand the current swap usage and its status.

Turn Off All Swap

~$ sudo swapoff -a
This command disables all active swap space. It’s necessary when you want to modify existing swap or create a new swap file. -a applies the command to all swap partitions/files.

Verify RAM and Swap Usage

~$ free -h
This command displays the current usage of RAM and swap space in a human-readable format. It helps you confirm that the swap space has been turned off. It also shows the available memory after disabling swap.

Create a New Swap File

~$ sudo fallocate -l 8G /swapfile
The fallocate command creates a file of a specified size, in this case, an 8 GB file named /swapfile. This file will be used as the swap space.

Set Correct Permissions for the Swap File

~$ sudo chmod 600 /swapfile
This command sets the file permissions to 600, ensuring that only the root user has read and write access to the /swapfile. This is important for security, as it prevents unauthorized access to the swap file.

Mark the File as Swap

~$ sudo mkswap /swapfile
This command sets up the /swapfile as a swap space. It prepares the file for use as swap by formatting it accordingly.

Enable the New Swap Space

~$ sudo swapon /swapfile
This command enables the /swapfile as active swap space, allowing the system to use it when necessary. At this point, the new swap space is ready for use.

Verify the Updated Swap Space

~$ free -h
Running this command again allows you to see the updated RAM and swap usage, confirming that the new swap space has been added and is now active.