Public cloud has clear benefits that are hard to achieve when using a private cloud. Let's take a detailed look at the benefits of public cloud. These benefits are the reason for all the attention that is being given to cloud computing:

One of the major benefits is the seemingly unlimited number of resources available in a public cloud. We call this cloud characteristic scalability. Additional processing power or storage is available on demand when requested; no need to order hardware and licenses, no need to wait for delivery, and no need to install hardware and software. Resources are ready by pressing a couple of buttons.

This offers great opportunities to deal with peaks in demand for resources. Think about a company that starts a new marketing campaign that will run for a couple of weeks. Instead of purchasing additional compute capacity to cover the peak, they just rent the capacity in the cloud: own the base, rent the peak.

Another benefit is agility, or elasticity as it is often called. Using cloud for your IT services means capacity is in sync with demand. Suppose your organization acquires another organization; you need 100 extra desktops and have two weeks to get this organized. Using cloud, the provisioning of those additional desktops is a matter of minutes. The same applies when demand is reduced. Suppose your organization needs to fire 100 employees; if the desktops of those employees are running virtually in the cloud, you can delete the desktops instantly. You are not stuck with assets you paid for but don't need anymore.

Scalability and elasticity is often used interchangeably. However, they are different as explained earlier. Scalability is a feature of the infrastructure that allows the addition of resources to cope with future demand.

Elasticity is the ability of a platform to automatically adapt to changing demand, either by adding workloads or removing workloads.

Availability is another big benefit of cloud. Does your organization have a secondary data center? Is data replicated to another location? Does your data center have enough resiliency when critical components fail? It might have all of these things, but this comes at a high cost. As resiliency is shared by many customers of the cloud service, the provider can offer this in a much more cost-effective way than single-tenant infrastructures.

Another benefit of cloud computing is outsourcing management of the physical infrastructure to the cloud provider. As a cloud consumer using an IaaS service, you only have to worry about managing the operating system and application with its data; there's no need to manage switches, firewalls, routers, servers, load balancers, and so on. To use SaaS, you don't have to worry about managing IT, except maybe managing identity management.

Last but not least, using cloud computing means a shift from investing an amount of money once (CapEx) to operational costs spread over multiple periods (OpEx). It also involves a shift from ownership to subscription. Because costs are now paid on a monthly basis, there is a much better insight into the costs. However, due to the complex cost structure and ease of deployment, there is a high risk that costs will be hard to manage. You have to make sure procedures are in place to monitor the consumption of new services. Most service providers do not offer a possibility to place a limit on the amount of costs per month (spending limit).

Some of the benefits mentioned previously are enablers for business process transformation. Cloud computing allows organizations to make it easier to meet their business goals. For example, because IT services are made available very quickly, products can be brought to market faster or cheaper. Alternatively, as the virtual desktops are running in the cloud, employees can work at any time or any place and are more productive and motivated.

While the benefits mentioned are clear and measureable, other so-called benefits are less clear. Many organizations believe that public cloud is cheaper than doing IT yourself. This is a typical case of it depends. For small deployments, cloud might be cheaper. However, for large deployments and especially when large amounts of high performance storage is needed, on-premises IT might be cheaper. It does pay off to do fair cost comparisons.

Cloud computing costs are constructed using the components that are consumed. The components are compute, storage usage, storage transactions, network traffic leaving the data center, support, additional services, and so on.

Keep in mind that when purchasing a storage solution, you pay only once. When consuming cloud storage, you pay each month for the storage and—in many cases—for transactions and data leaving the cloud as well.