"Going on-prem" almost never means building your own data center with generators, cooling towers, and a physical security team. For most companies, it means Colocation ("Colo") — a model that gives you the economics of owning hardware without the burden of owning a building.
What is Colo?
You rent rack space, power, and network connectivity from a specialist provider. The major players are Equinix, Digital Realty, and CoreSite.
- They provide: The physical building, precision cooling, redundant power (including diesel generators), physical security (biometric access, cameras), and high-bandwidth internet uplinks.
- You provide: The servers, network switches, storage arrays, and all the software that runs on them.
Think of it as the difference between renting an apartment (colo) and renting a fully furnished hotel room (public cloud). In the apartment, you bring your own furniture and appliances, but your monthly rent is a fraction of the hotel rate.
The Responsibility Shift
This is the most important operational difference to internalize:
| Responsibility | Public Cloud | Colocation |
|---|---|---|
| Physical building | Provider | Provider |
| Power & cooling | Provider | Provider |
| Network uplinks | Provider | Provider |
| Physical servers | Provider | You |
| Hard drive replacement | Provider | You (or "Smart Hands") |
| Hypervisor / OS | Provider (managed) or You | You |
| Software & applications | You | You |
"Smart Hands" is a colo industry term for contracted technicians at the facility who can physically touch your equipment on your behalf — swapping a failed drive, rebooting a server, or running a cable — without you needing to fly to the data center.
The core trade-off: You exchange engineering effort (managing hardware, responding to disk failures, planning capacity) for massive cost savings. Whether that trade is worth it depends entirely on your team's capacity and the scale of your savings.
A common interview question is: "What's the difference between colocation and on-premises?" Many candidates conflate them. Colo means your hardware, their building. True on-premises means your hardware, your building. Most repatriation projects target colo, not true on-prem, because building and operating a data center requires specialized facilities expertise that most software companies don't have.