With the arrival of cloud computing, it looks like every business these days is making its switch from traditional computing to the cloud, and for good reason. Nothing else claims to deliver so many benefits and cost savings at the same time. Because of the sudden popularity, the number of cloud service providers have risen. However, all of these services are not the same, as there are two major types of cloud services, “public cloud” and “private cloud.” There are several key differences between the two types that ultimately put public clouds on top while showing private clouds to be a poor substitute.
The first big issue is the cost of operating a cloud. In a public cloud, all the capital expenditures for the physical hardware and infrastructure are the responsibilities of the service provider. On the other hand, in a private cloud, customers not only must pay for all capital expense, but also are responsible for any handling or data management. This is the same for operational costs, for which the cloud provider is solely responsible in public clouds, while the customer is charged in private clouds. This is possible simply because public cloud providers can offer their services for a much lower cost due to their pre-existing infrastructure.
The next issue is reliability. Public clouds are available most of the time with SLA’s to back up any maintenance that might cause downtime. For instance, Gmail maintained a 99.984% uptime in 2010 and had no scheduled downtimes. As you might expect, private clouds require frequent maintenance checks and have more scheduled downtimes. They could become more reliable, but that would also mean an exponential rise in costs. Scalability is yet another issue. Public clouds can expand easily and are highly scalable. Whether you need to add thousands or even tens of thousands of users, public clouds can merge them into their infrastructure in a self-service fashion. Private clouds can scale, but they do so in increments, such as every 500 to 1000 users, and there are significant costs to do so.
Although the debate will most likely continue, it is clear that the claims of private clouds providing all the benefits of their public counterparts are false. In fact, it makes little or no sense to pay the extra fees when public clouds provide better services and features at a lower cost. One could even argue that private cloud computing is only an attempt for IT vendors to take advantage of a current hype to make extra profits.