Definition
Colocation (often shortened to colo) is a hosting model where you own the server hardware outright and a data-centre provider rents you secure rack space, power, cooling, physical security and network connectivity. You ship or install your own servers, storage and networking gear into a cabinet, cage or private suite, and the provider handles the building, the electricity feed, the fire suppression and the cross-connects to carriers and cloud on-ramps. You keep full control of the operating system, configuration, patching and upgrade cycle; remote-hands staff handle physical tasks like reboots or drive swaps on request, usually billed hourly. Colocation is the default for enterprises and infrastructure teams with specific hardware requirements, large server fleets, or compliance rules that require owned, auditable hardware. Pricing is typically quoted per U (rack unit), per cabinet, or per cage, bundled with a fixed kW power allowance; overage draws extra charges. Equinix and Digital Realty lead the global market.
How it works
You buy the server, ship it to the data centre, and the colo provider racks it, powers it, cools it, and connects it to their network. You retain ownership and full administrative control; the provider supplies "remote hands" for physical work like reboots or hardware swaps.
Why it matters
Colocation is right when you need full hardware control, predictable per-unit costs at large scale, specific cross-connects to cloud or partner networks, or compliance constraints that prefer hardware ownership. It is overkill for small footprints, where dedicated hosting is simpler.