How to Configure Swappiness in Ubuntu?
Tags: ubuntu
Published: 2021-11-25 10:12:07

---
title: How to Configure Swappiness in Ubuntu?
published: true
date: 2021-11-25 09:49:14 UTC
tags: Ubuntu
canonical_url: https://stackallflow.com/ubuntu/how-to-configure-swappiness-in-ubuntu/
---

<header>
<p><span style="font-size: 1.2em; color: initial;">memory usage</span><span style="font-size: 1.2em; color: initial;">swap</span></p>
</header>

I need a step-by-step, simple and easy way to configure swappiness.

#### Accepted Answer

The Linux kernel provides a tweakable setting that controls how often the swap file is used, called swappiness.

A swappiness setting of **zero** means that the disk will be avoided unless absolutely necessary (you run out of memory), while a swappiness setting of **100** means that programs will be swapped to disk almost instantly.

Ubuntu system comes with a default of 60, meaning that the swap file will be used fairly often if the memory usage is around half of my RAM. You can check your own system’s swappiness value by running:

```
one@onezero:~$ cat /proc/sys/vm/swappiness
60

```

As I have 4 GB of RAM I’d like to turn that down to 10 or 15. The swap file will then only be used when my RAM usage is around **80** or **90** percent. To change the system swappiness value, open `/etc/sysctl.conf` as **root**. Then, change or add this line to the file:

```
vm.swappiness = 10

```

Apply the change.

```
sudo sysctl -p

```

You can also change the value while your system is still running with:

```
sysctl vm.swappiness=10

```

You can also clear your swap by running `swapoff -a` and then `swapon -a` as root instead of rebooting to achieve the same effect.

To calculate your swap Formula:

```
free -m (total) / 100 = A

A * 10

root@onezero:/home/one# free -m
             total used free shared buffers cached
Mem: 3950 2262 1687 0 407 952
-/+ buffers/cache: 903 3047
Swap: 1953 0 1953

```

> so total is 3950 / 100 = 39.5 \* 10 = 395

So what it mean is that when **10 %** (395 MB) of ram is left then it will start using swap.

* * *

##                                           [Help . Ubuntu . Swap](https://help.ubuntu.com/community/SwapFaq)

##                                            What is swappiness

The swappiness parameter controls the tendency of the kernel to move processes out of physical memory and onto the swap disk. Because disks are much slower than RAM, this can lead to slower response times for system and applications if processes are too aggressively moved out of memory.

- `swappiness` can have a value between 0 and 100.
- `swappiness=0`:
  - Kernel version 3.5 and newer: disables swapiness.
  - Kernel version older than 3.5: avoids swapping processes out of physical memory for as long as possible.
- `swappiness=1`:
  - Kernel version 3.5 and over: minimum swappiness without disabling it entirely.
- `swappiness=100`:
  - Tells the kernel to aggressively swap processes out of physical memory and move them to swap cache.

See [http://en.wikipedia.org/wiki/Swappiness](http://en.wikipedia.org/wiki/Swappiness).

The default setting in Ubuntu is `swappiness=60`. Reducing the default value of swappiness will probably improve overall performance for a typical Ubuntu desktop installation. A value of `swappiness=10` is recommended, but feel free to experiment.

* * *

## Example

Started using swap at **91%** :

![enter image description here](https://i.stack.imgur.com/psR7c.jpg) As I have configured my system & vm to make use of RAM at **90%** , at **90%** there was no swapping.

After that I opened some applications like Firefox & Shutter, and it started swapping because RAM usage is above **90%**.

The post [How to Configure Swappiness in Ubuntu?](https://stackallflow.com/ubuntu/how-to-configure-swappiness-in-ubuntu/) appeared first on [Stack All Flow](https://stackallflow.com).