IaaS vs PaaS vs SaaS: How to Choose What's Best for You

Essentially, most cloud services fall into one of three categories, each with differing levels of service offered by the provider. These are Software as a Service (SaaS), Platform as a Service (PaaS) and Infrastructure as Service (IaaS). As the names suggest, they all deliver IT tools on a service basis, with the provider owning and managing the assets.

But each of these offer businesses differing levels of control, from allowing users to retain the management of key applications to handing over every aspect of your IT to a service provider. For most businesses, the first question when looking to establish cloud solutions will therefore be which model is best-suited to their needs.

Three cloud service models

Here we offer a rundown of each of the three main cloud service models, their advantages and limitations, and some of the best scenarios for each:

• Software as a Service
• Platform as a Service
• Infrastructure as a Service

What is SaaS?

Perhaps the most common form of cloud computing, SaaS refers to cloud-based applications. Most of these can be accessed and used through a web browser and won't require users to download software to their machine. Some of the most familiar SaaS applications are email services such as Gmail, business applications like Salesforce and file-sharing offers such as Dropbox.

What are the benefits of SaaS?

• SaaS products are cloud-based, meaning applications can be accessed remotely from any device
• Cloud service providers are responsible for managing and maintaining the platform, so you won't have to worry about licensing issues, patches and updates or the tedious process of rolling out the tools to every PC and laptop
• The majority of providers offer a monthly subscription model, meaning you'll be able to budget accordingly

The limitations of SaaS

One of the biggest issues with public SaaS is a lack of fine control and customization options. They’re often presented as a 'one-size-fits-all' solution as many customers will share the same platform. This means you may have to make compromises on features or won’t be able to develop a system tailored to your unique needs. You'll also be dependent on your chosen vendor for security and availability, and it may be difficult to integrate cloud options with on-premise applications or data.

When should I use it?

SaaS tools are ideal if you need reliable, up-to-date applications, but you don't have the resources available - in terms of time or money - to handle all the associated admin. It can also come in handy for short-term projects that require a lot of collaboration, or for applications that are only used occasionally, as the subscription model means they can be easily procured as and when they are required.

Learn more: Transform Legacy Systems: Make the Switch to SaaS with Minimal Disruption

What is PaaS?

PaaS tools offer developers a framework on which they can build their own software applications, offering all the tools that professionals need to complete the process, including the necessary operating systems, software updates, storage and infrastructure. Popular PaaS solutions include Google App Engine and OpenShift.

What are the benefits of PaaS?

• PaaS vendors typically manage and maintain the platform, freeing developers to focus on building applications
• Developers can access all the tools they need in one package
• You don't have to start from scratch when building applications, reducing the cost and the amount of coding needed
• The tools are scalable, so they can be used for projects of any size and ramped up if required

The limitations of PaaS

Like with SaaS, you may find your options for customization limited when using PaaS solutions. What's more, you'll only have direct control over the code you build yourself and not the underlying infrastructure supporting it. What's more, the data will be stored by the provider, which can create security issues, while users may also find there are limitations on what they can do with the tools, as they may not be optimized for the language and frameworks they prefer to work in.

When should I use it?

These solutions are ideal for software developers who need flexibility and cost-effectiveness, as well as the ability to work closely with others. It allows these professionals to focus more closely on the creative side of their work without having to worry about more mundane tasks, such as managing software updates. When building customized applications, PaaS can greatly reduce costs and simplify the development process.

Learn more: 5 Ways Successful PaaS Adoption Will Impact Your Enterprise

What is IaaS?

The third major cloud computing category, IaaS can be thought of as a virtual data center, providing all the basic infrastructure your business needs to operate, including servers, storage, and networking resources. While the provider manages these services, the customer maintains responsibility for all the applications, runtime, operating systems and data that use it. Amazon Web Services EC2 and Microsoft Azure are among the most widely-used IaaS services.

What are the benefits of IaaS?

• No upfront costs or capital costs are associated with IaaS
• Most providers adopt a PAYG model, so you only pay for what you use
• Vendors are responsible for hosting and managing the infrastructure, allowing you to focus on your priorities
• You can easily scale up or down as your requirements change while retaining full control over your infrastructure
• Infrastructure won't be affected if the server goes offline

The limitations of IaaS

While IaaS offers businesses a higher level of control, it's much more hands-on than other forms of cloud computing, and you're left to your own devices to configure everything at your end. This means you need to devote extra resources to managing the deployment and ensuring your team has the skills and training needed to do this. As customers are also directly responsible for issues such as security, backups and business continuity, if anything does go wrong, it's up to you to have a good disaster recovery plan in place.

When should I use it?

IaaS is a great option for rapidly-expanding businesses that need to build an IT estate fast. It means you won't be locked into a specific hardware or software environment that may not be suitable in the future, and its useful for everything from web hosting and testing to high-performance computing operations, such as big data analytics. This means it's also a great option for large enterprises looking to add new services.

Learn more: IaaS: What Every CIO Needs to Know Before Migrating

Which cloud service model is best for your organization?

The decision on which cloud service model to use will be dependent on what your business goals are. Each offers similar benefits in terms of flexibility, scalability and choice, but the exact services they provide will vary depending on your needs.

One analogy is to consider cloud computing like a vehicle. If you own your own car, you're responsible for everything from the driving to the maintenance, like traditional on-premises computing.

Alternatively, IaaS can be considered similar to leasing a car - you're still in control of the driving, filling it with gas, etc, but you don't actually own the machinery - and if your needs change you can always swap it for a different car.

Meanwhile, PaaS is more like hailing a cab, as you still have your own private environment and destination, but you get to sit back and let the driver handle the work.

Finally, SaaS is more like a bus, with an assigned route that you hop on and off as needed, along with other passengers.

Ultimately, you still end up where you want to go, but the level of control you maintain over how you get their will vary, so consider what your firm wants to do. If you need out-of-the-box software with little customization, a SaaS service will be ideal, but if you're building a new website from scratch, IaaS will be the better option.

Further Reading

• PaaS vs Serverless Computing: Which One Should You Adopt?
• How to Develop a Cloud Decision Framework
• 5 Ways to Break Free from Cloud Vendor Lock-In