# Rack diagram

A rack elevation is a specific, unglamorous, extremely useful diagram: which unit holds what, front and rear. It belongs next to the runbook, because that is when somebody needs it.

RackDiag generates elevations from a short text description, so keeping them current is cheap.

---

## When to reach for one

* Data centre and comms room documentation.
* Planning an install, where the units have to add up.
* Remote hands instructions, where the unit number is the instruction.

---

## How to draw it in Capable

| **Route** | **Use when**                                               |
| --------- | ---------------------------------------------------------- |
| RackDiag  | Generated elevations from text; ideal for keeping current. |
| draw.io   | Photorealistic elevations with vendor-specific shapes.     |

---

## A worked example

A rack elevation, unit by unit:

![Rack diagram](https://help.gocapable.com/images/att1417969694.svg)

The source, which you can paste into a new diagram and edit:

```
rackdiag {
  16U;
  1: UPS [2U];
  3: Patch panel;
  4: Core switch;
  5: ToR switch;
  7: Server 01 [2U];
  9: Server 02 [2U];
  11: Storage array [4U];
}
```

---

## A few things that catch people out

* Number from the bottom, as racks are numbered in the room.
* Draw the rear if anything about cabling or power matters.
* Leave the gaps visible; empty units are capacity, and capacity is the reason people look.

---

## Related

[Data center diagramFloor, rows, racks, and power.](https://help.gocapable.com/diagrams/data-center-diagram.html)

[Packet and protocol headersBit offsets, drawn properly.](https://help.gocapable.com/diagrams/packet-and-protocol-headers.html)

[ExamplesWorking diagrams you can copy.](https://help.gocapable.com/diagrams/examples.html)

---

_Somebody will read this at 3am. Be kind._