How To Add Swap Space on Debian 10

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:

vim /etc/fstab

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

vm.swappiness=10

Now reload the sysctl configuration file

sudo sysctl -p

Conclusion

In this tutorial, you have learned to create and enable Swap memory on Debian system.