{ pkgs, config, lib, ... }: { options.mods.zfs.enable = lib.mkOption { type = lib.types.bool; default = false; description = "does this system support zfs filesystems"; }; config = lib.mkIf config.mods.zfs.enable { boot.kernelPackages = pkgs.linuxPackages; boot.supportedFilesystems = [ "zfs" ]; }; }