One of the main benefits of cloud computing is the ability to offload tasks to an organization that can manage them faster, better, or cheaper than you can. But before you decide how much of your IT workloads you want to migrate to the cloud, you need to understand the differences between the three levels of services: SaaS, IaaS, and PaaS.

What is Software as a Service (SaaS)?

We’ll start here because SaaS is often the organization’s first introduction to cloud computing. SaaS is software offered as a service (usually on a subscription-basis) through the cloud. The rapid “SaaS-ification” of applications by vendors has shifted many organizations from having to manage and maintain software along with infrastructure to simply just consuming an application as needed. Some popular solutions started out as SaaS-only offerings and were never offered in an on-premises version. Salesforce (originally Salesforce.com) is probably one of the best-known examples.

Other applications, like Microsoft Office, started out as on-premises applications, but then offered a SaaS version (Office 365). In some cases, such as Microsoft Office and Office 365, the SaaS and on-premises versions can work together across the enterprise.

The ability to convert capital investments into monthly, predictable operating expenses is a common reason for migrating to SaaS. Another reason is that SaaS applications tend to receive features and benefits faster. Many of these applications continue to be offered in both on-premises and SaaS versions, but we expect to see more and more of the on-premises versions retired in the years ahead. We are already seeing enterprises following the “replacement” methodology where they replace certain apps with the SaaS versions or a similar product offered via SaaS.

What is Infrastructure as a Service (IaaS)?

Once organizations are comfortable with the concept of having workloads in the cloud, the logical next step is to start migrating workloads that aren’t cloud-native to either a public or private, hosted cloud.

Public cloud  

Public cloud refers to a cloud environment where physical compute and storage resources are shared among multiple “tenants.” The top three public cloud providers are Amazon (AWS), Microsoft (Azure), and Google (GCP), although many smaller providers also offer multitenant cloud environments.

Private cloud  

In a private cloud environment, physical resources are reserved for one organization’s use only. In some cases (colocation, for example) these resources may remain the property of the enterprise even though they are housed in a third-party data center.

While it may seem like a minimal move to re-host your workloads in the cloud, it can give you back considerable time that was otherwise spent on managing infrastructure. As organizations progress along their journey to digital transformation, finding a well-positioned IaaS cloud can set an organization up for time savings and create bandwidth needed for the more complex workload transformations.

IaaS delivers the most essential elements of a cloud: physical servers and storage, operating systems, hypervisors and virtual machines, as well as networking. IaaS can be a do-it-yourself proposition where your team manages the cloud environment remotely. However, many organizations will work with managed service providers to migrate workloads to the cloud as well as provide additional services such as disaster recovery and security & compliance. Look for managed service providers that offer these services a la carte so you can select the services that complement the skills of your in-house team.

What is Platform as a Service (PaaS)?

Platform as a Service offers both cloud-based infrastructure and tools for managing environments designed to develop, test, deliver, and manage software applications. Though PaaS sounds like an offering that would be used only by software companies, it is rapidly being adopted by enterprises as more and more of them develop SaaS solutions to complement their products and services or for in-house use. This includes analytics tools as well as a wide array of applications.

SaaS vs. PaaS vs. IaaS: which one, or which combination, is right for you?

As you might imagine, many organizations will have workloads deployed across all three types of environments. For example, they might use several cloud-native SaaS applications as well as have migrated some of their mission-critical applications to a private, hosted IaaS environment. For dev/test, they’ll use PaaS, but then they may migrate their production workloads to either a private or public cloud environment (IaaS) for additional security and compliance.

The possible configurations of SaaS, PaaS, and IaaS really are endless. The key is to choose the right level of cloud service for your workload and your environment. If you have questions about which environment is right for your needs, we’re happy to help.

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