Forrester Research expects the global private cloud solutions market to grow at a Compound Annual Growth Rate of 11% from 2016 to 2021. While this is certainly small compared to the growth rate of public cloud solutions, it still means there are enterprises out there who are interested in using private clouds. But when would you likely choose a private cloud over a public cloud?

When you want better control and customisability

A public cloud infrastructure is always managed by a third party. That means, while you control the virtual machines, operating systems, and applications of your cloud environment, you don’t control the underlying physical network, storage devices, and servers. The people who’ll be configuring, administering, and troubleshooting the physical infrastructure aren’t going to be from your organisation.

This can be a major stumbling block if you prefer certain ways of doing things or if you need to implement highly specialised configurations. What if you want to conduct low-level customisations that involve both software and hardware? What if you need to integrate your cloud environment with existing legacy IT systems and those systems are only compatible with certain hardware solutions? You need control over the entire infrastructure to tackle these issues.

This limitation in public clouds is one reason why some enterprises prefer private clouds or why some businesses maintain a private cloud while also using a public cloud infrastructure - a  combination known as a hybrid cloud.

Of course, setting up a private cloud won’t be a walk in the park. Unless you already have cloud experts in your IT department, you will need to partner with a trusted private cloud service provider (CSP) who can guide you along the way. They can also assist you in your customisation and integration projects.

Your lack of control in public clouds can have serious implications in the area of security, privacy, and compliance, which leads us to the second reason why you would choose a private cloud over a public cloud.

When you worry about security, privacy, and compliance issues

While there are certainly exceptions, public clouds are generally considered less secure than private clouds. As a matter of fact, research firm Gartner recently stated that “security and/or privacy concerns continue to be the top inhibitors to public cloud adoption”.

Because organisations have virtually zero control over the underlying physical infrastructure, they can’t be absolutely sure whether adequate security is being enforced in that area. For instance, they may not know for certain whether:

1. The (Cloud Service Provider) CSP’s engineers underwent proper vetting;
2. Strict access control policies are being enforced on physical servers;
3. The CSP’s data centre is resilient enough to withstand fire, earthquake, and other man-made or natural calamities.

In addition, there are concerns as to where data and virtual machines are stored. They might be replicated to the CSP’s data centres located overseas, a major issue for UK businesses, who need to comply with the Data Protection Act (DPA).

The DPA requires that personal data “shall not be transferred to any country or territory outside the European Economic Area (EEA) unless that country or territory ensures an adequate level of protection for the rights and freedoms of data subjects in relation to the processing of personal data.”

These issues are almost absent in private clouds. Because you have full control over underlying private cloud storage, network, and servers, you can architect, implement, and enforce security from the ground up. You control where data and VMs are stored and make sure security measures meet compliance requirements.

It’s worth noting that most security and privacy concerns can be addressed by a virtual private cloud solution, i.e. a dedicated pool of storage, networking, and computing resources carved out of a public cloud, so this is something worth considering.

When you need and can afford superior performance and availability

When you subscribe with a public cloud provider, you normally can’t choose exactly what physical servers and hypervisors, as well as networking and storage devices, are going to be used. What if you wish to architect the underlying infrastructure (including power and cooling) and have specific hardware requirements to ensure topnotch performance and availability?

With a private cloud, you can purchase hardware and build the infrastructure according to your desired specifications. You can select high-performance CPUs and high IOPS storage devices. And, in order to achieve high nines of availability, you can apply as many levels of redundancy if you want. There are ways to greatly reduce latency and increase workload capacity in a private cloud as long as you have the talent and the budget.

Conclusion

Although private clouds generally can’t match the economic benefits of public clouds, they still offer benefits many businesses find extremely important. If control, security, and performance are crucial to your business and you feel public clouds can’t meet your requirements in these areas, then a private cloud should be a better fit.