Introduction
Enterprise colocation remains a critical component of infrastructure strategy for organisations that need predictable performance, regulatory compliance, and hands-on hardware access. Unlike public cloud, colocation gives you full control over your hardware while leveraging a provider's power, cooling, physical security, and connectivity.
But not all colocation providers are equal. The UK market has seen significant consolidation, and the difference between a good colocation partner and a mediocre one can mean hundreds of thousands of pounds in operational costs over a multi-year contract.
This guide covers what enterprise buyers need to evaluate before signing a colocation agreement.
Power Density: The #1 Decision Factor
Modern enterprise hardware — especially GPU nodes, dense storage arrays, and high-performance compute — draws significantly more power than previous generations. A standard rack that needed 5-7kW five years ago now needs 20-30kW or more.
When evaluating a colocation provider, ask:
- What's the maximum power density per rack? Many older facilities cap out at 10-15kW per rack. That's insufficient for modern hardware.
- Is power billed metered or by circuit? Metered billing is more transparent and lets you pay for what you actually use.
- What's the power redundancy? 2N redundancy means two independent power paths. N+1 means one backup. For mission-critical workloads, 2N is the minimum.
- What's the PUE (Power Usage Effectiveness)? Lower PUE means more efficient cooling and lower operational costs. Look for PUE below 1.4.
Power Cost Estimation
At UK commercial electricity rates (~£0.15-0.25/kWh), a 10kW rack costs approximately £13,000-£22,000 per year in power alone. A 30kW GPU rack could cost £40,000-£65,000 annually. These numbers should factor heavily into your total cost of ownership calculations.
Connectivity and Cross-Connects
Network connectivity is the second most critical factor. Your colocation provider's peering and carrier diversity directly impact your latency, throughput, and reliability.
Key questions to ask:
- How many carriers are on-net? More carriers mean better pricing and redundancy. Look for facilities with 10+ carriers.
- What's the cross-connect pricing? Some providers charge £200-500/month per cross-connect. This adds up quickly if you need multiple connections.
- Is there an on-net IXP (Internet Exchange Point)? London has LINX, Manchester has IXManchester, and Scotland has IXScotland. Direct peering at an IXP improves latency and reduces transit costs.
- What's the maximum port speed? 10G and 100G should be available. 400G is becoming important for large-scale deployments.
Physical Security
Enterprise colocation facilities should have defence-in-depth security:
- Mantraps with biometric and card access
- 24/7 on-site security personnel
- Continuous CCTV monitoring with 90-day retention
- Visitor logs and escort policies
- Individual cage or cabinet locks with audit trails
- Loading bay security and delivery verification
Ask for their SOC 2 Type II or ISO 27001 certification. UK colocation providers should also comply with the UK's National Cyber Security Centre (NCSC) guidelines for critical infrastructure.
SLA Fine Print
Service Level Agreements are where colocation providers differ most. Don't just look at the uptime percentage — read the fine print:
| SLA Component | What to Look For | Red Flags |
|---|---|---|
| Power Uptime | 99.999% (5 minutes downtime per year) | 99.9% (8.7 hours/year) — unacceptable for enterprise |
| Network Uptime | 99.99% with multiple diverse fibre paths | Single fibre entry point |
| Cooling Uptime | N+1 or 2N cooling redundancy | N (no redundancy) cooling |
| Response Time | 15 minutes for critical issues, 24/7/365 | 1 hour+ response, business hours only |
| Credits | 5-10% monthly credit per 30 minutes of downtime | Credits only apply after 4+ hours of downtime |
UK-Specific Considerations
The UK colocation market has unique characteristics that enterprise buyers should understand:
London vs Regional Data Centres
London (especially Docklands, Slough, and the M4 corridor) has the highest concentration of data centres in the UK. It offers the best connectivity but comes at a premium. Regional facilities in Manchester, Leeds, Edinburgh, and Cardiff offer lower costs and good local connectivity.
Brexit Implications
Post-Brexit, data flows between the UK and EU are governed by the UK's adequacy decision (currently under review). Ensure your colocation provider has clear policies on cross-border data transfer and can demonstrate compliance with both UK GDPR and EU GDPR if needed.
The UK's Climate Resilience
The UK's temperate climate means cooling costs are lower than in hotter regions. However, extreme weather events (heatwaves, flooding) are becoming more frequent. Ask about flood risk assessments and cooling system resilience during record temperatures.
Total Cost of Ownership
Beyond the monthly rack fee, colocation TCO includes:
- Power — typically £0.10-0.20/kWh
- Cross-connects — £200-500/month each
- IP transit — £5-20/Mbps depending on commit
- Remote hands — £100-200/hour for physical assistance
- Cage/cabinet add-ons — shelves, PDUs, fibre management
- Insurance — your hardware, their building
A typical half-rack with 5kW power, 1G transit, and basic remote hands runs £1,500-3,000/month in a London facility. Regional facilities are typically 20-30% cheaper.
How Hostingowy Approaches Colocation
We run our own hardware in European data centres (Poland). Rather than reselling third-party colocation, we own the servers, the network, and the support experience. This means:
- No middleman markup on colocation services
- Our engineers are the same people who rack and maintain the hardware
- We can offer custom configurations (custom BIOS, GPU passthrough, dedicated VLANs)
- Transparent pricing with no hidden fees
For enterprises that need dedicated infrastructure in the UK, we offer colocation-aligned dedicated servers and private cloud solutions with full hardware isolation.
Conclusion
Choosing a colocation partner is a long-term decision. Evaluate power density, connectivity, security, SLAs, and total cost of ownership carefully. Visit the facility in person. Talk to existing customers. Read the SLA's fine print.
The right colocation partner is one that treats infrastructure as a partnership, not a commodity transaction.