Server colocation looks simple on paper: rent a slot in a data centre, install your server, plug in power and network, done. In practice, there are a handful of things that catch new colocation customers out. Here are eleven things to know before you sign a contract.
1. What you actually get
Space (1U through to a full 45U rack), power (typically two redundant A+B feeds), cooling, IP transit, physical security and 24/7 site access. Your hardware, your operating system, and your applications stay your responsibility.
2. Power is sized in kilowatts, not amps
Modern servers draw more power than they used to. A common mistake is sizing colocation by rack units when the kW envelope is the real ceiling. Ask your provider how many kW you can draw per cabinet, not just how many U you have. We size quarter, half and full rack plans by both.
3. A+B power redundancy is standard, not optional
Two independent power feeds per cabinet, each backed by UPS and generator. If your server only has one PSU, you are wasting half the resilience you are paying for. Dual PSU server hardware is cheap insurance.
4. Network bandwidth is usually included, but with caveats
Most UK colocation plans include a 100 Mbit or 1 Gbit port with a sensible monthly traffic allowance. Check whether the allowance is fair-use, 95th-percentile billed, or a hard cap. Ours is unmetered on standard ports with no surprise bills.
5. Cooling is hot aisle / cold aisle, not just AC
Modern data centres use hot/cold aisle containment to keep server intakes at a stable temperature. You may be asked to install blanking panels in unused U so airflow stays correct. Worth checking before you ship hardware.
6. Physical security is layered
Reception with photo ID, mantrap, biometric or key card access, internal CCTV, locked cages. For ISO 27001 compliance, all of this matters and you should ask to see the auditor’s report.
7. 24/7 access exists, but is by appointment
You can visit your hardware day or night, but you book the slot in advance so the on-site team is expecting you. Walking in unannounced is not a thing. Bring photo ID, sign the visitor log.
8. Remote hands is the unsung hero
Most colocation contracts include 15 to 30 minutes of remote hands per month. Use it for power-cycling a stuck server, swapping a hot-spare drive, checking a cable, reading a console message. Anything beyond the included allowance is billed per 15 minutes.
9. IP allocation is small and justified
RIPE policy means IPv4 allocations are tight. Plan to use one or two public IPv4s per server, ideally with proper IPv6 dual-stack on top, not a /29 just because you asked. Justification on the order form is normal and required.
10. ISO 27001 matters more than ever
If your customers ask where their data lives, ISO 27001 certification on the facility is the answer they want. UK-based, audited yearly, evidence of physical, network and personnel security controls. Worth paying a little more for.
11. Pricing is monthly, with a few add-ons
Most reputable UK providers price colocation as a flat monthly fee per cabinet size, with extras for extra power, extra IPs, cross-connects or significant remote hands work. Avoid anything with a setup fee on basic plans, or anything that locks you in for years.
Where to start
If you are sizing your first colocation, look at our Single Server Colocation (1U to 4U) for compact deployments, or Quarter Rack Colocation from £162.50 per month if you have 5U or more. Both run from our UK Sheffield ISO 27001 data centre, with the 24/7 access, A+B power, remote hands and Tier 1 network described above.
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