Server Rack
Native data-centre rack elevations, and the only one that checks whether the rack can actually be built. Set the height in `units` and place each `device` at a top U with a height, optionally with its `power` and `weight`; the engine reports two devices claiming the same unit (drawn one over the other, so the figure shows one where the document declares two), any device that reaches past either end of the rack (silently clamped by every tool that draws what it is handed), free capacity and the tallest device that would still fit, and the declared draw and mass against the rack's stated budgets.
In the same space
Most users come to Server Rack from Visio rack stencils or rackdiag. flowss runs this engine in the browser — no install, shareable via URL, exportable to PNG / SVG / PDF / source.
Syntax at a glance
units 24
power 4000 W
device "Switch" at 24 height 1 power 320 weight 9Paste this in the Studio code pane to see Server Rack render live. The full grammar is at the upstream-docs link above.
Sample templates
All 8 →The one to copy. A 42U cabinet with a stated power budget and floor loading, every device in a unit of its own, nothing reaching past either end, and headroom stated in both watts and kilograms. The panel reports the free capacity and the tallest device that would still fit, which is the number somebody planning the next install actually wants. Reports clean.
Two devices declared at U 20, in a rack where everything else is spaced correctly. Drawn by any tool that draws what it is handed, the second is painted over the first at full width and the first disappears — so the figure shows seven devices where the document declares eight, in a plausible slot with a plausible label, and nothing anywhere says a device is missing. Here they are drawn side by side in the unit they contend for, ringed, and the panel names both.
A 4U storage shelf placed at U 3, which reaches down to U 0 — a unit that does not exist — and a switch placed at U 30 in a 24U cabinet. The renderer this replaces clamped the top unit with `Math.min(units, at)`, so in a 12U rack a device at U 12, at U 20 and at U 99 produced byte-identical SVG: the author's mistake silently corrected into a drawing of a rack they never described. Neither device is drawn mounted here; both appear in a marked strip beside the frame, at the unit they claim.
Eight compute nodes in a 42U cabinet, every one in a unit of its own, nothing overhanging — an elevation that is correct in every way a drawing can be. It draws 5,280 W against a 4,000 W budget, and there is no arrangement of boxes that shows it: twenty servers fit in a rack whether they draw 4 kW or 14 kW, and the elevation is identical either way. Stated per device and per rack, it is exact arithmetic with no heuristics in it.
The rack states a power budget and not one device states its draw, so there is nothing to add up. Reported as a GAP naming what is missing rather than as a budget that was met — a green tick over an unknown is worse than no tick at all, and a reader who sees findings and no gaps takes the reading as total. The occupancy half of the analysis still runs and still finds every device in a unit of its own, because two questions that can be answered separately should be.
A 24U rack elevation for a small stack.
rack · ← Browse all engines · Quick-start guide