No matter how large a company or what industry they work in, you'd struggle to find a business today that doesn't use some form of data centre or cloud computing service. But the two terms are frequently confused — and understanding the distinction matters when you're making decisions about where your business data and infrastructure actually lives.
Let's start with the definitions
A data centre is a physical facility that provides the infrastructure required to house and operate computing equipment. At its core, a data centre provides four things:
- Power — in sufficient quantity, quality, and redundancy to run the equipment continuously
- Cooling — to counteract the heat generated by servers, storage, and networking gear
- Reliability — through redundant systems, backup generators, and engineered resilience
- Security — physical access controls, surveillance, and security personnel to protect the equipment
Data centres range in size from a few racks in a small facility to hyperscale facilities covering tens of thousands of square metres consuming tens of megawatts of power.
Cloud computing means using computing resources — processing power, storage, applications — that are owned and operated by someone else, accessed over the internet. When a business uses Microsoft 365, they're using cloud computing. When a developer runs workloads on AWS, they're using cloud computing.
The crucial connection
Here's where the confusion usually lives: the cloud and data centres are not alternatives to each other. The cloud depends entirely on data centres.
When you store a file in Microsoft OneDrive, it's physically sitting on a server in a Microsoft data centre — probably one of several, in multiple geographic locations. When you run a virtual machine in AWS, it's running on physical hardware in an Amazon data centre. There is no cloud without physical infrastructure — there's just physical infrastructure you don't have to see or manage yourself.
The three main types of cloud service
Software as a Service (SaaS)
You use an application over the internet and the provider handles everything else. Microsoft 365, Salesforce, Xero, and Google Workspace are all SaaS products. You don't manage any infrastructure — you just log in and use the software.
Infrastructure as a Service (IaaS)
You rent computing resources — servers, storage, networking — and use them to run your own operating systems and applications. AWS EC2, Microsoft Azure Virtual Machines, and Google Compute Engine are IaaS products. You're responsible for what runs on the infrastructure; the provider manages the hardware.
Platform as a Service (PaaS)
A layer above IaaS — the provider manages the infrastructure and the platform (operating system, runtime environment) and you deploy your applications on top. Less common for business users, more relevant for developers.
So what does this mean for your business?
Understanding the distinction helps you ask better questions when evaluating where your systems should live.
"Should we use the cloud?" is actually several different questions: Should we use cloud software (SaaS)? Should we run our own servers in a cloud provider's data centre (IaaS)? Should we co-locate our physical servers in a third-party data centre? Or should we continue to house our own servers on-premises?
Most businesses today use a mix. Core productivity tools (email, documents, collaboration) are typically SaaS. Business-specific applications may run on IaaS or on co-located physical servers. Some systems — particularly those requiring specific hardware or with low latency requirements — remain on-premises.
The right answer depends on your specific workloads, your compliance requirements, your IT capability, and your tolerance for vendor dependency. It's worth thinking through carefully rather than defaulting to "everything to the cloud" or "keep it all in-house."