NixOS makes that too, its whole "system output path closure" is as immutable as every single store unit within it. But NixOS "reuses" units which are unaffected by NixOS config changes when applying new config, making its "system rebuild" super fast and light on resources when something like a single config file is changed in NixOS config. And possible to be done "in place", unlike with "conventional immutable distro"
NixOS makes that too, its whole "system output path closure" is as immutable as every single store unit within it. But NixOS "reuses" units which are unaffected by NixOS config changes when applying new config, making its "system rebuild" super fast and light on resources when something like a single config file is changed in NixOS config. And possible to be done "in place", unlike with "conventional immutable distro"