Colocation, cloud and on-premises infrastructure are operating models, not simple quality rankings. Each moves responsibility, cost and control to different places.

1) On-premises infrastructure

On-premises systems are operated in a facility controlled by the organization, such as an office server room or private data centre. This can provide direct control over equipment and access.

The organization is also responsible for power, cooling, connectivity, physical security, hardware, staffing and recovery unless those services are separately contracted.

2) Colocation

In colocation, the organization owns or controls equipment installed in a provider-operated data centre. The provider normally supplies space, power, cooling, physical security and carrier access.

The customer remains responsible for servers, storage, software and much of the architecture. Remote-hands services may assist with physical tasks.

3) Cloud infrastructure

Cloud services provide compute, storage, networking and managed platforms through provider-controlled infrastructure. Resources can often be provisioned quickly and billed by use or reservation.

The provider manages more of the physical stack, while the customer remains responsible for service design, configuration, identity, data, monitoring and recovery choices.

4) Responsibility comparison

AreaOn-premisesColocationCloud
Facility and utilitiesOrganizationProviderProvider
HardwareOrganizationOrganizationProvider
Architecture and configurationOrganizationOrganizationCustomer/provider split
Capacity expansionProcurement projectProcurement plus rack spaceUsually rapid, cost must be managed
Physical accessDirectProvider-controlled accessGenerally no customer access

5) Decision factors

  • Workload stability and growth
  • Required control and physical access
  • Staff skills and operating coverage
  • Recovery objectives and geographic needs
  • Capital versus operating cost preference
  • Compliance, data location and contract requirements

6) Hybrid designs

Many organizations use more than one model. A hybrid design can place stable or specialized systems in owned equipment while using cloud services for elasticity, managed platforms or geographic reach.

Hybrid infrastructure adds integration and dependency questions. Identity, networking, monitoring and recovery must work across environments.

Operational review questions

Use these questions to connect the concept to a real service or environment:

  • Which business services depend on this layer?
  • Who owns operation, maintenance and recovery?
  • Which suppliers and shared services are involved?
  • What happens during maintenance or partial failure?
  • What evidence shows the design works as intended?