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Datacentre Simulation

Cnuas models a hyperscale AI campus as one artefact, from the silicon up to the site. The rack that runs the workload is emulated in software, and the campus that would house it is generated as an OpenUSD stage that opens in NVIDIA Isaac Sim or any USD viewer.

The two halves are joined. Site electrical load is computed from the same racks the emulator runs, so a change in the compute load moves the number on the grid connection. Nothing here is driven by a synthetic trace.

The film

A walk through the generated campus, the buildings, the data halls, and the two racks that Cnuas actually emulates. Every rectangle in the film is drawn from the output of plan.plan_campus(), so it is the same geometry the OpenUSD exporter writes to the stage. (MP4, 2:14, with narration.)

The campus

The reference campus, default_campus(), is a 1,000 by 800 metre site holding three datacentre buildings, sixteen data halls, 1,920 racks and a 291 MW facility load.

Plan of the Cnuas Ridge AI Campus, generated from the model

Every rectangle in that plan is read from the same planner the USD exporter consumes, so the drawing and the stage cannot disagree.

The building shapes are not styling. In an H or an E the central spine carries the electrical and mechanical plant while the data halls occupy the limbs, so every busway run and every pipe header stays short. The shape is the distribution strategy made visible.

Building Shape Data halls Racks
DC1 I, linear 4 480
DC2 H 6 720
DC3 E 6 720

Buildings sit west of the north to south service spine. Plant yards, the utility substation, cooling water storage, the administration building and parking sit east of it, which keeps the route from the loading dock to any hall short and gives a fire appliance a way to every face of every building. Two retention ponds and four planted screening belts complete the site. The ponds are amenity, and they are also stormwater and thermal infrastructure, which is why real campuses have them.

Inside a data hall

Fifteen of the sixteen halls are emitted as named volumes carrying a rack count and a load. One hall, DH1 in DC1, is emitted rack by rack.

Rack level plan of data hall DH1

The two racks in orange are the ORv3 racks the emulator runs. They carry a telemetry attribute on the USD prim:

cnuas:telemetry:source = "modbus-rtu://127.0.0.1:3485/0xc0"

That address is a real power supply on the emulated ORV3 power shelf. Reading PSU_Output_Voltage and PSU_Output_Current from it gives a measured wattage that is written back onto cnuas:power:drawKw, which is how the campus is driven by the emulator rather than by a spreadsheet.

The floor is deliberately not full. A liquid cooled AI hall runs out of power and cooling long before it runs out of floor, so the remaining area goes to coolant distribution and to the next phase.

The rack Cnuas emulates

The two rack Cnuas reference deployment

Two racks on the Open Compute Project Open Rack v3, each carrying two 1OU top of rack switches, a management host, and eight 2OU blades. Every blade is a guest with an emulated RDMA adapter and one or more emulated accelerators. The whole deployment runs on one workstation.

The numbers

The power roll up is computed, not quoted. Change the rack count or the rack type and every figure below moves, including the number of generators.

Quantity Value
Racks 1,920
IT load 253.2 MW
Design PUE 1.15
Facility overhead 38.0 MW
Grid connection 291.2 MW
Heat to reject 253.2 MW
White space 23,040 m2
Power density 11.0 kW/m2
Standby generators 99 at 3 MW

Each building carries the full TIA-942-B room programme, from the Entrance Room and Meet-Me Room through the Main Distribution Area to the data hall, with a Horizontal Distribution Area, coolant distribution room and fan wall gallery per hall, plus the medium voltage switchgear, transformer vault, paralleling switchgear, battery, pump and water treatment rooms that make a building run.

Generate it yourself

pip3 install -e facility

cnuas-facility power                     # the power roll-up, no USD needed
cnuas-facility rooms                     # the room programme, per building
cnuas-facility build --out campus.usda   # the OpenUSD stage

Open campus.usda in NVIDIA Isaac Sim, usdview, Blender, or any other USD capable tool. To drive the stage from the emulated power shelf:

cnuas-facility live --duration 60

The plans on this page are regenerated with:

python3 facility/scripts/render_plan.py --out docs/assets/facility

Where to read further