Data centre facilities are the building, power, cooling, security and cables that a data centre provides before a single server is installed. The company that runs the facility is called a data centre operator. It sells space, electricity and connections, not computing.
The best-known business here is colocation. The operator rents out racks, locked cages of several racks, or whole rooms, and the tenants bring their own servers. Guards, cameras, biometric doors and locked cages let many companies share one building without reaching each other's machines. This sharing is called multi-tenancy.
What many tenants value most is the neighbours. Cloud providers, telecom operators and internet exchanges keep equipment in the same building. An internet exchange is a place where many networks connect and pass traffic directly to each other. Cross-connects, short fibre cables across the hall, join a tenant to these neighbours. A cross-connect is faster and cheaper than sending the same traffic over the public internet.
The largest running cost is electricity. Data centre power and cooling equipment carries power from the grid to every rack. Batteries keep the servers running for the short time that the diesel generators need to start. Cooling equipment then removes the heat that the servers produce. For example, a building whose servers use 10 megawatts may use another 4 to 5 megawatts for cooling, lighting and losses.
Not every data centre is a large building. A modular data centre fits inside a shipping container. It can be placed at a mine or another remote site, where it does edge computing: computing done close to where the data is produced.
AI is changing the facility more than anything else. An AI rack can draw more than ten times the power of an ordinary rack. So operators now choose new sites first for their electricity supply, and they are adding liquid cooling to their halls.