{
  "default": "go_cpu",
  "volumes": {
    "main": {
      "sectors": {
        "0,0,0,0": {
          "layers": {
            "0": {"backend": "go_cpu"},
            "1": {"backend": "metal"},
            "2": {"backend": "metal"}
          }
        }
      }
    }
  }
}