Whenever someone talks about advantages of cloud computing they say flexibility and scalability. When using a public cloud, when I'm not using the power, someone else is, but what about a private cloud? Lets say a company uses a private cloud. If the company is growing, adding more hypervisors or storage space does the trick. But what if the company needs the extra power only on some particular times of the month/year etc? Do private clouds still have this advantage of upscaling during peaks and going back throughout the rest of the time?
If you mean by private cloud, an on site or 'Infrastructure as a service' (IaaS) then the answer is that itcanprovide scalability.
- If there are multiples services on the private cloud with different busy hour profiles (i.e. they are busiest at different times of the day) then each service can scale up and down as needed
- Some IaaS solutions will actually allow you to power down servers etc when they are not being used, hence saving on power and cooling etc (which can be significant in large installations)
However, they clearly do not offer the same flexibility as large public cloud providers.
Private cloud could also mean a 'reserved' or 'ring fenced' part of a public cloud - in this case the power down option is generally not available.
In both cases above, a combined private/public approach would allow core load on the private cloud with overflow to the public cloud for peaks etc. This can have economic benefits if an organisation believes it can host the private cloud portions more cheaply than a public cloud offering.