What is the difference between public cloud and private cloud?
Thankfully for us, the years of explaining what the cloud is have largely passed. Instead, the questions have shifted to what the best ‘type’ of cloud is for individual businesses: what the different kinds of cloud architecture are, and which ones best align with an organisation’s commercial objectives, security requirements, and budget.
For many businesses, this decision ultimately boils down to the choice between public and private cloud environments. Having spent decades helping organisations bridge the gap between traditional IT and the modern workplace, we’ve seen the evolution of both models first-hand. Here’s the difference between the public and private cloud, and why understanding them both is pivotal for building a resilient and future-proof digital estate.
What is public cloud computing?
Public cloud computing refers to IT services that are delivered over the internet, and shared among multiple organisations. In this model, the hardware the cloud relies on (the servers, storage, and networking equipment) is owned and operated by a third-party provider. These providers, often global giants like Microsoft Azure or Amazon Web Services, host thousands of customers’ data in a mass of global, interconnected data centres.
The primary characteristic of the public cloud is that it’s multi-tenant. While your data is walled off and secured from other users, it will be on the same machine and using the same physical resources as countless other businesses. This shared approach allows for incredible economies of scale, making it a highly cost-effective option in many cases. It’s a particularly popular hosting environment for general-purpose applications like Microsoft 365, and as an environment for app development or testing.
The public cloud acts much like a utility, where cost is more of an issue than supply. Instead of worrying about maintenance, you simply pay for the capacity you consume. This pay-as-you-go model is great for rapid experimentation and fluctuations in demand, as the huge capacity of these providers allows you to scale your investment near-instantly without needing to invest in (and then configure) physical hardware.
What does a public cloud infrastructure service do?
A public cloud infrastructure service, often categorised as Infrastructure as a Service (IaaS), provides the fundamental building blocks of on-demand computing. Instead of purchasing physical servers and housing them in your own offices, you rent virtualised versions of these resources from a provider’s global network. This involves using a virtual machine (VM) on a server, allowing one powerful server to act like multiple, less powerful virtual PCs.
The primary function of public cloud services is to offload the burden of hardware management. The provider takes full responsibility for things like cooling the server rooms, keeping them secure, addressing hardware failures, and upgrading components to improve performance. This frees up your internal IT team to stop thinking about maintenance, and focus on more long-term or strategic projects.
Today’s public cloud infrastructure services have become highly sophisticated. Thanks to new and advanced AI-driven management tools, they can now handle:
- Elastic scaling, automatically adding or removing server capacity in real-time to match your workload demand.
- Geographic distribution, allowing you to host your applications in data centres across the globe to reduce latency for international users.
- Integrated compliance, meeting certification requirements (such as ISO 27001 or SOC 2) that can be prohibitively expensive for many individual businesses.
Leveraging these services unlocks a world of potential for businesses, at a price point that scales to your requirements and ambition. Even a relatively small investment can give you access to world-class technology that can power everything from simple websites to complex machine-learning models, all without the need for your own on-premises hardware.
What are private cloud services?
Private cloud services provide a cloud environment that is dedicated exclusively to a single organisation. Unlike the public model, where you share physical hardware with other tenants, a private cloud offers single tenancy. This means that every server, storage array, and network switch in that environment is yours and yours alone.
A private cloud can be hosted in two ways: internally on your own premises, or externally within a third-party data centre. At Sota, we operate our own high-security data centre campus, providing hosted private cloud services to organisations nationwide. This offers the best of both worlds: the flexibility of the cloud with the absolute control and security of dedicated hardware.
The advent of GDPR and data security accreditations are creating growing demand for both data sovereignty and customisation. Because the environment isn’t shared, you have complete authority over the security policies, the hardware configuration, and the network settings used. This level of customisation is vital for organisations handling highly sensitive data like financial records, medical records, or proprietary research, and is something a managed service provider like Sota can help you to implement on a private cloud.
Private clouds also eliminate the ‘noisy neighbour’ effect. In a public cloud, while each VM gets its own proportion of system resources, bandwidth is finite, and a sudden spike in traffic from another tenant sharing your server can occasionally impact your performance. In a private cloud, your resources are absolutely guaranteed, ensuring more consistent and low-latency performance for important business applications.
Private vs public cloud: which one should you choose?
Deciding between a private or public cloud model isn’t about finding the better technology, but about identifying the right fit for your specific operational needs. With both private and public cloud models offering their own benefits, the organisations we work with are increasingly finding that a hybrid approach allows them to best utilise the strengths of both.
The public cloud is usually the best choice when:
- You need scalability due to variable or unpredictable workloads.
- You need to get apps to market quickly, as you can quickly provision new resources for testing and deployment.
- You want to minimise expenditure, due to the simple and scalable pricing model.
The private cloud is often the superior option when:
- Security and compliance are key due to operating in a highly regulated industry.
- You have mission-critical apps that require consistent, reliable infrastructure.
- You need a more stable, fixed-cost structure for steady workloads.
Ultimately, the goal is to build a digital estate that empowers your workforce and secures your future. At Sota, we specialise in architecting these environments, whether that involves a transition to the global scale of Microsoft Azure, or the sovereign security of our own private data centres.
By choosing a partner with 35 years of technical heritage and a family-business commitment to service, you’re investing in a dependable and powerful ally in your digital transformation. Visit our Managed Cloud page to learn more, or get in touch with us today.