[Nix-dev] split current and old profile builds

[James Cook]

On 28 November 2016 at 20:13, Stefan Huchler <stefan.huchler at mail.de> wrote:
> I was so cracy that I installed nixos on a 16gb chromebook. which makes
> every update now very hard, because of space problems.
>
> So well then I thought I have this 64gb sd(hx?) card lets just move the
> whole /nix/store there. But when I run a hdparm -tT performance test I
> got I think 17mb/s vs 170mb/s read results sdcard vs internal flash.
>
> So I would prefer to not slow my complete system down by putting it
> completly on the sdcard, but I would like to have some history to revert
> back to something.
>
> Is there a way to keep only the packages form the current profile on the
> internal flash and move old stuff to the sdcard?
>
> Or should I use some sort of raid (btrfs maybe) to spread the files over
> both devises.
>
> I also thought about putting all on the sdcard but have a very big swap
> file on the internal flash. But I think the System dont has to swap much
> on my setup. so the first read would be where it counts.
>
> Or maybe just install for the user the packages he needs most under his
> user profile, like the browser which I restart very often.
>
> Is there some nixos-way to do that?
>
> Or any suggestions would be nice.
>
> Thanks

Have you looked into SSD caching? I have not tried it myself, but
something like dm-cache might be what you're looking for.

James