What is a private cloud exactly? And what are the advantages and disadvantages to this approach to machine virtualisation?
In the term 'private cloud' the word 'private' does not relate to the security of the virtual machines, nor does it relate to the data or applications that run on them. Instead, the word private relates to the exclusive use of the platform on which the virtual machines, applications and data reside.A private cloud is a physical cloud infrastructure that is wholly dedicated to one organisation. Virtual machines can be created on that infrastructure for the exclusive use of that entity. This means that when your company invests in private cloud, you are obtaining access to your own host hardware, hypervisor, RAM, storage and networking - none of which is shared with any other user.
Advantages of private cloud
To say that a private cloud has advantages over public cloud is not to say that it is always the better choice, there are other factors that affect that decision. But, when private cloud is an appropriate choice, it offers these benefits:
- Enhanced security and privacy: In addition to the perfectly robust security that is possible on individual virtual machines, a private cloud can be isolated from all but the company who owns it. This restricted access, which can integrate with a firm's firewall and other remote access policies, offers an additional layer of security.
- Improved reliability: When compared to either dedicated hardware or public cloud alternatives, private cloud offers a greater degree of reliability thanks to a fault resilient and redundant architecture that isn't shared in any way.
- Improved performance: The resources within your private cloud infrastructure are at the disposal of your company and your company alone. There is no contention with other companies for capacity (only with your own workloads) and far less chance that a malicious attack against another firm will affect your ability to function.
- Increased flexibility: Unlike a physical machine, a virtual machine can be scaled up and down seamlessly. And when you own all the virtual machines, you can reallocate resources dynamically, wherever they are needed most.
- Total control: Although there is a fair amount of universal best practice that you should no doubt follow, you are free to build and configure your private cloud in any way you like. For example, you have the freedom to use any operating systems and applications you please and to allocate resources in any way you see fit.
As with all things, as well as advantages private cloud has, under some circumstances, disadvantages.
Disadvantages of private cloud
- Cost: With exclusivity comes increased cost. If you plan to build your own private cloud, you face a large capital outlay. Fortunately, you can rent your private cloud from a hosting service provider, for a monthly fee, and still benefit from all the advantages.
- Under-utilisation: With a private cloud, the cost of capacity under-utilisation is a cost to you, not to your provider. Therefore managing and maximising utilisation becomes your concern.
- Platform scaling: Since you are unlikely to want to retain significant, un-utilised capacity, based on the previous point, large upward changes in your requirements are likely to require scaling of the physical infrastructure. This is fine but may take longer than simply scaling a virtual machine within existing capacity.
In-house or outsourced private cloud
The term private cloud may lead some to think that a business has to own their private cloud infrastructure outright, building it up in their own offices or data centre suites. While this is perfectly possible and may be appropriate in some cases, it is also possible to place your private cloud requirement with a third party service provider. Doing so typically enables you to derive economic benefits from their existing presence in the data centre environment, including advantageous access to power and internet connectivity along with protection from fire, theft and malicious damage.
Is private cloud right for you?
Virtual machines on both public and private cloud configurations are more-or-less capable of the same things, so it may not be clear which solution is better suited to you.
Private cloud can definitely be used to achieve higher levels of security and reliability and so may be suited to organisations with sensitive, business critical workloads or in regulated industries such as financial services. Even if this is not you, your specific requirement may make private cloud a sensible route to go as, for some users, private cloud 'ownership' can be more cost effective, in the long run, than public cloud usage.
If you plan to outsource your cloud computing requirements to a service provider, our best advice is to select a provider you trust and work with their solution architects and account managers to identify the perfect solution for you.