Private vs Public Cloud

Once an organization has chosen to pursue a cloud computing strategy, the next major decision will be whether to use a public cloud service or to set up a private cloud.

It’s important to note that the private vs. public cloud decision doesn’t have to be an either-or choice. Industry analysts say that most enterprises are pursuing a multi-cloud strategy; that is, they use more than cloud. In fact, the 2017 Rightscale State of the Cloud Survey found that, on average, enterprises are running applications in 1.8 public clouds and 2.3 private clouds, while experimenting with another 1.8 public clouds and 2.1 private clouds.
In addition, many organizations are pursuing a hybrid cloud approach, which means they use at least one public cloud and at least one private cloud that they manage as a single environment.

These hybrid and multi-cloud strategies allow organizations to choose the best type of cloud for particular workloads. Each deployment model — public, private, or hybrid cloud — has its own strengths and weaknesses, making it uniquely suited for particular use cases.
So what are those strengths and weaknesses? And when should enterprises use each type?

Public Cloud Computing

Like the name suggests, a public cloud is available to anyone in the general public. These cloud computing services are operated by vendors with extremely large data centers with computing and storage resources that are shared among all of the vendors’ customers.

Public Cloud Pros:
Agility: When asked about their reasons for choosing public vs private clouds, many enterprises put agility at the top of the list. Public clouds enable users to provision and deploy new computing resources almost instantly, allowing organizations to achieve faster time-to-market with new products and services. In addition, it’s very easy to alter the mix of computing resources being used as an organization‘s needs change over time.

Scalability: Similarly, as application usage or data grows, it’s very easy to add more computing resources to meet demand. Many public cloud services include automated scaling so that organizations don’t even have to think about adding more compute instances or storage — it just happens automatically.

Availability: While public cloud outages get a lot of press — usually because they affect a lot of organizations — in general, public clouds provide more uptime than traditional data centers or private clouds that organizations host in their own data centers. Many enterprises choose to incorporate public cloud services into their business continuity (BC) and disaster recovery (DR) plans because they can use a cloud-based service that is geographically distant from their own data centers, which provides an extra layer of protection in case of a natural disaster.

Performance: If you need high-performance computing (HPC) resources for some of your workloads, the public cloud makes it easy to access HPC capabilities and only pay for what you use. By contrast, installing HPC systems in your own data center can be a very expensive proposition. In addition, large public cloud providers can afford to install the latest technology in their data centers, unlike smaller organizations that may have a longer refresh cycle.

Low Costs: Because they are so large, public cloud data centers achieve economies of scale that most enterprises can only dream of. That allows public cloud vendors to drive prices incredibly low. The public cloud also saves users money by reducing or eliminating the need for IT staff to manage your own hardware and by charging based on usage, which gets rid of the need to overprovision servers to deal with surges in demand. Also, the public cloud converts some capital expenses (the one-time costs of purchasing hardware and software) to operational expenses (recurring subscription fees), which can look good on a company‘s financial statements.