# How to add a swap after NixOs installation
**URL:** https://discourse.nixos.org/t/how-to-add-a-swap-after-nixos-installation/41742
**Category:** Help
**Created:** [March 18, 2024, 1:53pm UTC](https://discourse.nixos.org/t/how-to-add-a-swap-after-nixos-installation/41742 "2024-03-18T13:53:23Z")
**Posts on this page:** 8
**Page:** 1
### Author:  [@AndreasL](https://discourse.nixos.org/u/AndreasL)
#### Post date: [March 18, 2024, 1:53pm UTC](https://discourse.nixos.org/t/how-to-add-a-swap-after-nixos-installation/41742/1 "2024-03-18T13:53:23Z")
Hi,
I’ve just installed NixOs 23.11 on a old laptop with _only_ 6Gb of RAM (btw I still didn’t a solution for [my sound card](https://discourse.nixos.org/t/no-sound-on-speaker-or-hdmi-on-dell-latitude-e5620/41665)) and just realize that with only Thunderbird and Firefox it get exhausted at the speed of light ! 😲
The problem is that I didn’t specify any `swap` partition when installing NixOs (I just ran the default option) so I got a `/` ext4 partition which take all the space.
How can I “fix” that ?
Usually, I would use a tool like `gparted` to reduce the size of my partition, and then create a swap, but I assume it doesn’t work like that on NixOs ?
My laptop did already freeze a couple of time because of missing memory space (I assume), so I would be glad to have a solution !
Thanks in advance for your help !
Andréas
---
### Author:  [@lelgenio](https://discourse.nixos.org/u/lelgenio)
#### Post date: [March 18, 2024, 2:37pm UTC](https://discourse.nixos.org/t/how-to-add-a-swap-after-nixos-installation/41742/2 "2024-03-18T14:37:25Z")
I think the easiest thing for you to do now would be to create a swapfile:
```nix
{
swapDevices = [{
device = "/swapfile";
size = 16 * 1024; # 16GB
}];
}
```
Just switch configurations and it should be created automatically.
---
### Author:  [@AndreasL](https://discourse.nixos.org/u/AndreasL)
#### Post date: [March 18, 2024, 3:10pm UTC](https://discourse.nixos.org/t/how-to-add-a-swap-after-nixos-installation/41742/3 "2024-03-18T15:10:58Z")
Thanks for your reply @lelgenio .
Will this configuration create the swapfile and automatically resize my main partition ?
I doubt that, or should I manually create the partition (with `gparted` for example) as I suggested above ?
---
### Author:  [@anon54679641](https://discourse.nixos.org/u/anon54679641)
#### Post date: [March 18, 2024, 3:56pm UTC](https://discourse.nixos.org/t/how-to-add-a-swap-after-nixos-installation/41742/4 "2024-03-18T15:56:21Z")
[Here](https://wiki.archlinux.org/title/Swap#) you can read about swap partition and swap file.
---
### Author:  [@lelgenio](https://discourse.nixos.org/u/lelgenio)
#### Post date: [March 18, 2024, 5:13pm UTC](https://discourse.nixos.org/t/how-to-add-a-swap-after-nixos-installation/41742/5 "2024-03-18T17:13:25Z")
> [@AndreasL](#):
>
> Will this configuration create the swapfile and automatically resize my main partition ?
> I doubt that, or should I manually create the partition (with `gparted` for example) as I suggested above ?
It will create the swap-file automatically. It’s a regular file, there’s no partitioning involved, you won’t need to do anything else.
> [@AndreasL](#):
>
> I doubt that
NixOs is a pathway to many abilities some consider… unnatural.
---
### Author:  [@Nebucatnetzer](https://discourse.nixos.org/u/Nebucatnetzer)
#### Post date: [March 18, 2024, 5:52pm UTC](https://discourse.nixos.org/t/how-to-add-a-swap-after-nixos-installation/41742/6 "2024-03-18T17:52:15Z")
I can confirm this works just fine.
Used it myself on all my systems a few weeks ago.
Another nice thing to do on devices with little RAM is ZRAM swap btw.
It uses a part of your RAM for swap but compresses it before storing.
[https://search.nixos.org/options?channel=23.11&show=zramSwap.enable&from=0&size=50&sort=relevance&type=packages&query=Zram](https://search.nixos.org/options?channel=23.11&show=zramSwap.enable&from=0&size=50&sort=relevance&type=packages&query=Zram)
The Linux Matters podcast talked about it as well:
> **[A Mini Swap Adventure - Linux Matters](https://pca.st/9ldvio54)**
>
> Join 3 experienced Open Source professionals as they discuss the impact Linux has in their daily lives. Upbeat family-friendly banter, conversation and discussion for Linux enthusiasts and casual observers of all ages. A new episode every two weeks...
---
### Author:  [@AndreasL](https://discourse.nixos.org/u/AndreasL)
#### Post date: [March 18, 2024, 10:36pm UTC](https://discourse.nixos.org/t/how-to-add-a-swap-after-nixos-installation/41742/7 "2024-03-18T22:36:24Z")
> [@lelgenio](#):
>
> It will create the swap-file automatically. It’s a regular file, there’s no partitioning involved, you won’t need to do anything else.
Ok nice, I didn’t know the swap was not a partition…
> [@lelgenio](#):
>
> NixOs is a pathway to many abilities some consider… unnatural.
🤣 You’re right, it’s quite an astonish Os ! To be honest I don’t understand why all the distribution out there don’t use a similar system for managing package and dependencies. It makes such sense !
---
### Author:  [@Nebucatnetzer](https://discourse.nixos.org/u/Nebucatnetzer)
#### Post date: [March 19, 2024, 4:26pm UTC](https://discourse.nixos.org/t/how-to-add-a-swap-after-nixos-installation/41742/8 "2024-03-19T16:26:38Z")
> [@AndreasL](#):
>
> Ok nice, I didn’t know the swap was not a partition…
It can be but doesn’t have to.