{ lib, config, ... }:
let cfg = config.custom.dataDisk;
in {
  options = {
    custom = {
      dataDisk.enable = lib.mkOption {
        default = false;
        type = lib.types.bool;
        description = ''
          Whether to automatically mount /dev/sda1 on /mnt/data
        '';
      };
    };
  };

  config = lib.mkIf cfg.enable {
    fileSystems."/mnt/data" = { device = "/dev/sda1"; };
  };
}