Manage Swap
Swap is a space on a disk that is used when the amount of physical RAM memory is full. When a Linux system runs out of RAM, inactive pages are moved from the RAM to the swap space.
If your system is running out of memory, you can create a swap file to increase the available memory.
However, for some systems, like distributed database systems, it is recommended to disable swap to avoid random performance issues.
Adjusting swap doesn't require a reboot
You can adjust the swap space without rebooting the system.
Swap file vs Swap Partition
A swap file is a file that is used as a swap space, while a swap partition is a dedicated partition that is used as a swap space.
A swap file is easier to create and manage than a swap partition, while a swap partition usually has better performance than a swap file.
Check if swap is enabled
To check if swap is enabled, run the following command:
sudo swapon --show
Also you can use the free command to check the overall memory usage and swap usage:
free -h
Create a swap file
To create a swap file, run the following commands:
sudo fallocate -l 8G /swapfile # You can change the size and the name of the swap file
sudo chmod 600 /swapfile
sudo mkswap /swapfile
To activate the swap file, run the following command:
sudo swapon /swapfile
To make the swap file permanent, add the following line to the /etc/fstab file:
echo '/swapfile none swap sw 0 0' | sudo tee -a /etc/fstab
Disable swap
To disable the swap, run the following command:
sudo swapoff -v /swapfile
To remove the swap file, run the following command:
sudo rm /swapfile
Don't forget to remove the swap file from the /etc/fstab file.
Totally disable swap
To totally disable swap, you can directly run the following command:
sudo swapoff -a
And that will disable all swap spaces.