# Questions about custom live iso
**URL:** https://discourse.nixos.org/t/questions-about-custom-live-iso/50789
**Category:** Help
**Created:** [August 18, 2024, 12:26pm UTC](https://discourse.nixos.org/t/questions-about-custom-live-iso/50789 "2024-08-18T12:26:48Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@retzx](https://discourse.nixos.org/u/retzx)
#### Post date: [August 18, 2024, 12:26pm UTC](https://discourse.nixos.org/t/questions-about-custom-live-iso/50789/1 "2024-08-18T12:26:49Z")
Hello, i have some questions about custom live iso NixOS the wiki is missing some information
First question how to have a live iso that boot more faster ? I’ve followed this guide [Copying NixOS's Live CD to RAM: a short look at NixOS's early boot](https://artemis.sh/2023/03/07/nixos-early-boot-running-from-ram.html) the goal was to get a custom live iso that run only in ram but… it takes around 2 or 3 minutes to copy the system on the ram it’s very slow… is there any solution about this ?
Second question how to minimize at maximum the size of the custom live iso ? My iso take 3,4 GB , i removed a lot of default packages i’ve heard about this [Custom ISO - limit size - #2 by hmenke](https://discourse.nixos.org/t/custom-iso-limit-size/11438/2) there is only [nixpkgs/nixos/modules/installer/cd-dvd/iso-image.nix at efd385f2d5e7ebdcf489509e78ddc7b9b60d70a4 · NixOS/nixpkgs · GitHub](https://github.com/NixOS/nixpkgs/blob/efd385f2d5e7ebdcf489509e78ddc7b9b60d70a4/nixos/modules/installer/cd-dvd/iso-image.nix) in my config but the iso is still big…
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### Author:  [@mightyiam](https://discourse.nixos.org/u/mightyiam)
#### Post date: [August 19, 2024, 5:47am UTC](https://discourse.nixos.org/t/questions-about-custom-live-iso/50789/2 "2024-08-19T05:47:03Z")
> [@retzx](#):
>
> First question how to have a live iso that boot more faster ? I’ve followed this guide [Copying NixOS’s Live CD to RAM: a short look at NixOS’s early boot](https://artemis.sh/2023/03/07/nixos-early-boot-running-from-ram.html) the goal was to get a custom live iso that run only in ram but… it takes around 2 or 3 minutes to copy the system on the ram it’s very slow… is there any solution about this ?
Yes, that would be slower, not faster. I don’t expect there would be easy ways to make it boot faster.
> [@retzx](#):
>
> Second question how to minimize at maximum the size of the custom live iso ?
I like “minimize at maximum”.
Try using `nix-tree` to explore the result.
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### Author:  [@retzx](https://discourse.nixos.org/u/retzx)
#### Post date: [August 26, 2024, 6:41pm UTC](https://discourse.nixos.org/t/questions-about-custom-live-iso/50789/3 "2024-08-26T18:41:29Z")
Thanks for responding i didn’t know about “nix-tree” i will check that 🙂