[Nix-dev] nix.maxJobs not working for system env?

[Mathijs Kwik]

Hi all,

I have nix.maxJobs = 8 in my configuration.nix.
This successfully writes "build-max-jobs = 8" in /etc/nix/nix.conf.

During builds I occasionally run
ps -ef | grep ^nixbld | cut -f1 -d\  | sort -u
to see how many builders are active.

Rebuilding my user environment (buildEnv) does use up to 8 builders,
so that works fine.

However, when running nixos-rebuild to build the system profile, it's
always just 1.
I'm pretty sure this used to work fine some time ago. I first noticed
it when rebuilding my entire system on the stdenv-updates branch, but
maybe it has been going on before.

Does anyone have a clue what might be causing this or how to investigate?

Thanks,
Mathijs