Many Linux distributions are configured out of the box in such a way that if your memory usage reaches a certain threshold or percentage of the total internal memory in your machine, it is switching over to use the swap space. The swap is a technique to use a special swap partition or swap file as additional virtual working memory. But using swap as virtual memory is of course much slower than your physical internal memory, so it should be used only when this additional memory is really required. But in practice some Linux systems switch over too soon. So let’s find out How to use your internal memory optimally in Linux, or in other words, how to configure your system swap settings optimally.
What is the problem
For example in Linux Mint or some other Ubuntu based systems the default value for the threshold is 60, which must be interpreted as that the swap virtual memory comes into operation when 40% of the physical RAM is in use, or when 60% of the memory is left available. This standard turning point of 60 is in my opinion a bit early, especially if you have an older system with only 2 or 4 GB of internal memory, which means that your system is continuously switching in and out of swap. My advice is to bring this value down from 60 to 10, which means that swap comes into operation when 90% of the physical RAM is in use, or when 10% of the memory is still available. This behaviour can be adjusted by defining the swappiness in the sysctl.conf file.
How to configure your system swap settings optimally
To better configure the threshold point to switch over to using swap you can go through the following steps to adjust the sysctl.conf file (steps based on Zorin OS 15t, but usable for other distros as well):
First let’s check the current value of the swap to see if what I was saying before is actually true in your specific situation:
1) Open a terminal session with the keyboard combination Ctrl + Alt + T.
2) Type in your terminal “cat /proc/sys/vm/swappiness” and give enter.
Here you can see that in my specific situation, a Zorin OS 15 installation, the swappiness value is indeed also 60, which means that my system will use only up to 40% of my internal memory before switching over to a swap file. We can do better than that.
1) Open again a terminal session with the keyboard combination Ctrl + Alt + T.
2) Type in your terminal “sudo xed /etc/sysctl.conf” and give enter.
An editor will be opened with elevated privileges. Here we can edit the sysctl.conf file.
If xed is not available on your system, you can install it in the following way:
- Open again a terminal session with the keyboard combination Ctrl + Alt + T.
- Type in your terminal “sudo add-apt-repository ppa:embrosyn/xapps” and give enter.
- Type in your terminal “sudo apt-get install xed” and give enter.
3) Go to the last line in the file and give enter to start with a new empty line.
4) Type “vm.swappiness=10”.
5) save the file and close the file.
6) Reboot your computer.
When the computer is up and running again you can check the new configuration.
7) Open a terminal session with the keyboard combination Ctrl + Alt + T.
8) Type “cat /proc/sys/vm/swappiness” and give enter.
Here you can see that the swappiness value is indeed 10 now, which means that your system will use up to 90% of your internal memory before switching over to a swap file. This should keep your system more responsive when using heavier workload as it longer uses only your physical hardware.