nixos-servers/nixos/modules/data-disk.nix

{ lib, config, ... }:
let cfg = config.lab.dataDisk;
in {
  options.lab.dataDisk = {
    enable = lib.mkOption {
      default = false;
      type = lib.types.bool;
      description = ''
        Whether to automatically mount a disk to be used as a data disk.
      '';
    };

    mountPoint = lib.mkOption {
      default = "/mnt/data";
      type = lib.types.str;
      description = ''
        Mount point of the data disk (if enabled).
      '';
    };

    devicePath = lib.mkOption {
      default = "/dev/sda1";
      type = lib.types.str;
      description = ''
        Path of the device to be used as a data disk.
      '';
    };
  };

  config = lib.mkIf cfg.enable {
    fileSystems.${cfg.mountPoint} = { device = cfg.devicePath; };
  };
}