How a false smoke alarm almost drowned Jane Street’s only NYC datacenter

A false smoke alarm at 1 New York Plaza forced Jane Street’s systems team to race against sprinkler activation in the firm’s only New York datacenter, which housed roughly 10 rows of server cabinets, an online UPS, CRAC cooling units and refrigerator-sized network switches. The incident, recounted by a former systems team member, exposed the risks of the firm’s long-standing insistence on keeping its machine room next to its trading floor—first for intellectual property protection, later so staff could physically pull power cords on runaway trading systems. That risk culture was shaped in part by a partner who had served on a nuclear submarine, reinforcing a preference for mechanically connected kill switches over automated safeguards. The datacenter grew from a small machine room serving about 10 people into a sizable facility as headcount reached 150, all crammed inside an otherwise ordinary skyscraper. The near-miss matters because it shows how physical infrastructure and manual overrides remained central to a sophisticated trading operation. What to watch next: whether Jane Street formalizes redundant datacenter capacity and cooling safeguards as it continues to grow.