Swap memory is a location on harddisk is used as Memory by the operating system. When the operating systems detects that main memory is getting full and required more RAM to run applications properly it check for swap space and transfer files there. In general terms, swap is a part of the hard disk used as RAM on the system.
This tutorial will help you to ADD Swap memory on Debian 10 Buster Linux system.
Add Swap in Debian 10
Use the below steps to create and enable Swap memory on your Debian system via command line.
1. Check Current Swap
First of all, Make sure your system have no Swap memory configured on your system. You can check if by running one of the below commands.
sudo swapon -s free -m
2. Create Swap file on Debian
Lets create a file to use for swap in system of required size. Before making file make sure you have enough free space on disk. Generally, it recommends that swap should be equal to double of installed physical memory.
My Debian system have 2GB of main memory. So we will create a swapfile of 4GB in size.
sudo fallocate -l 4G /swapfile chmod 600 /swapfile
The, make it to swap format and activate on your system by running following commands:
sudo mkswap /swapfile sudo swapon /swapfile
3. Make Swap Permanent
After running above commands, Swap memory is added to your system and operating system can use when required. But after reboot of system swap will deactivate again.
You can make it permanent by appending the following entry in /etc/fstab file. Edit fstab file in editor:
and add below entry to end of file:
/swapfile none swap sw 0 0
Save file and close. Now Swap memory will remain activate after system reboots.
4. Verify Swap Memory
You have successfully added swap memory to your system. Execute one of the below commands to view current active swap memory on your system:
sudo swapon -s free -m
5. Update Swappiness Parameter
Now change the swappiness kernel parameter as per your requirement. It tells the system how often system utilize this swap area.
Edit /etc/sysctl.conf file:
sudo vim /etc/sysctl.conf
append following configuration to end of file
Now reload the sysctl configuration file
sudo sysctl -p
In this tutorial, you have learned to create and enable Swap memory on Debian system.