Available rack positions
The cheapest constraint to discover and the most awkward to relieve, because it is somebody's tenancy.
What runs out
Rack positions that can actually be released for the new deployment.
The relation that governs it
Positions available, not positions installed. A hall with 560 positions and 380 under contract has 180.
How to tell whether it binds in your hall
Count what you can genuinely empty inside the programme. If that is fewer than the racks the power and cooling would allow, this binds — and it binds on commercial terms, not engineering ones.
What relieves it
Release positions from existing tenancy, or consolidate.
What that relief costs beyond money
Commercial and contractual, not capital. The lead time is a negotiation, which makes it the hardest item on the ladder to programme honestly.
Indicative relief lead time
4–20 weeks
European retrofits. The schedule, not the capex, usually decides.
The mistake we actually see
Counting installed positions rather than releasable ones, which overstates the envelope before any physics is done.
Basis
- — Site tenancy records.
These usually travel together
Does this one bind in your hall?
Seven numbers you already know, all thirteen constraints evaluated, and the one that stops you first named with its basis in engineering units. Free.