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Architecture and Design

When we are talking about IT infrastructure the terms architecture and design seem to be used with identical meaning – even by practising architects who should know better.

The two concepts are quite different.

A architecture is how we want deliver – the concept if you like.  I have seen this level labelled as conceptual design which in many ways is a better label than architecture. As an example we will consider the Windows server estate of an organization. It has been decided that architecturally the roadmap is to virtualise. Our architecture looks like this

  • Server farm  - hosts for virtualisation
  • hyper-visor and management system for virtual machines
  • SAN based storage for virtual machines

For simplicity I’ll leave out backup, networks etc etc. They are assumed to be present.

Notice that I haven’t mentioned a single product. Architectures are product agnostic.

A design is what we will actually implement.

There are a number of designs we could create to satisfy this architecture.

For instance:

  • 5 IBM based servers
  • VMware + vcenter


  • 5 HP servers
  • Microsoft Hyper-V + SC Virtual Machine Manager

we could continue building options. In many cases buying policy and/or existing infrastructure dictate the solution.

In any case these designs have the same architecture but they have different designs and implementations.

Architecture is product independent – Design is when we decide on the components we are using and pick the products.

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