What is cloud computing?

What it means

Instead of buying a server and keeping it in your building, you rent capacity from a provider's data centers over the internet. You can start, resize or stop it as needed and are billed for the time and capacity used, which is called pay-as-you-go.

The word covers two common things. One is rented infrastructure, such as virtual machines in Microsoft Azure that you manage yourself. The other is software as a service, where the provider runs the whole application and you pay per user to sign in, as with Microsoft 365. The opposite arrangement is on-premises IT.

Why it matters to a business

• Flexible cost: you swap a large up-front purchase for a recurring bill, which is easier to start but needs watching as usage grows.
• Less hardware to maintain: the provider looks after the physical equipment, though you still own your settings, access and data.
• Reach: staff in several locations can use the same systems without a server in each office.
• Shared responsibility: backups, security configuration and compliance are not automatic. You still have to plan and test them.

How this shows up in our work

We work with Microsoft Azure, hybrid setups, and migrations in both directions between on-premises and cloud, and we write the recovery plans that go with them. Each workload gets its own answer, and sometimes the answer is to keep it on servers you own.

Learn more

• Cloud computing on WikipediaA neutral overview of cloud service models and how they developed, helpful for non-specialists.
• Microsoft AzureThe provider's own site, with service descriptions for teams considering Azure.