Public cloud or private cloud: which should your business choose?
Performance, cost, security, compliance: the real differences between public and private cloud, and a simple method to choose — or combine both.
It’s one of the first infrastructure decisions: public cloud or private cloud? The good news is there’s no wrong answer in absolute terms — only an answer suited to your workload. Here’s how to decide.
The difference in one picture
- Public cloud: you rent resources on a shared infrastructure with other customers. Fast to start, billed by usage, ideal for flexibility.
- Private cloud: infrastructure dedicated to you alone. Guaranteed resources, complete isolation, ideal for critical and sensitive workloads.
Both offer the same management flexibility (create, clone, resize a VM in a few clicks). The difference is whether the physical infrastructure is shared — or not.
The comparison that helps you decide
| Criterion | Public cloud | Private cloud |
|---|---|---|
| Setup | Immediate | Fast (dedicated sizing) |
| Cost | Pay-as-you-go, low to start | Fixed, predictable |
| Performance | Variable | Guaranteed resources |
| Isolation / security | Good | Maximum |
| Ideal for | Sites, apps, variable loads | Critical, sensitive data, compliance |
When to choose public cloud
Public cloud is the right choice when:
- your load is variable (traffic spikes, one-off projects);
- you want to start fast and pay by usage;
- the application tolerates slightly fluctuating performance;
- you have no hardware-isolation requirement.
A website, a growing SaaS app, a test environment: all perfect cases for public.
When to choose private cloud
Private cloud is the way to go when:
- you handle sensitive or regulated data;
- performance must not vary (business database, ERP);
- you must demonstrate strict isolation and compliance;
- you prefer a fixed monthly cost over a usage-based bill.
To go deeper, see: Private cloud: what it is, who it’s for.
What if the answer is “both”?
In practice, many companies adopt a hybrid approach: critical and sensitive on private cloud, variable and public-facing on public cloud. You get the best of both — guaranteed resources where you need them, flexibility and pay-as-you-go elsewhere.
The key is not getting locked in. At Rēzau, public and private coexist on the same sovereign infrastructure, hosted in Quebec and Ontario, with $0 egress fees — you move workloads from one to the other with no penalty.
Frequently asked questions
Is private cloud safer than public? It offers superior hardware isolation. But a well-run, sovereign public cloud is already very secure. The choice mostly depends on your compliance and performance requirements.
Can you start on public and migrate to private? Yes. With no egress fees, moving a workload from public to private (or the reverse) happens with no nasty surprise on the bill.
Which costs less? Public for variable loads; private for sustained and critical loads, thanks to its predictability. The real math is based on your actual usage.
Not sure which is right for you? Compare our public cloud and private cloud offerings, or create your account to get a price and talk it through with our team.