IaaS vs. PaaS vs. SaaS: How to choose?
Explore the unique advantages of infrastructure as a service, platform as a service and software as a service.
Anne Siess
IT professional
When people refer to cloud computing models, they’re often referring to cloud services models. The three core cloud services models are:
Cloud services models dictate who is responsible for what. Your organization’s requirements to this end are what determine the best model for your organization.
What’s the Difference Between IaaS, PaaS and SaaS?
IaaS, or Infrastructure-as-a-Service
IaaS provides fundamental computing infrastructure such as servers, networking tools and processing power that you can purchase and use on-demand from a vendor.
PaaS, or Platform-as-a-Service
PaaS gives developers a ready-to-use platform for building applications, including infrastructure. A PaaS platform lets developers create complex applications and manage data, but offload maintenance tasks and infrastructure.
SaaS, or Software-as-a-Service
SaaS lets you use software on-demand without worrying about installing, upgrading or maintaining that software or the infrastructure.
Examples of each cloud model will be provided in their respective sections below.
How do I Choose Between IaaS, PaaS and SaaS?
Whether an IaaS, PaaS or SaaS solution is right for you depends on your business requirements. One option isn’t fundamentally better or worse, they simply address different needs.
With IaaS, you only get bare-bones infrastructure. This means that you will still need resources and staff with the technical know-how to buy, install, configure, manage and maintain whichever applications and operating systems you want to run on that infrastructure. While PaaS and SaaS both have infrastructure built in, PaaS is an environment better suited for software developers, while SaaS is designed to better meet the hands-on needs of everyday business users.
Let’s take a closer look at IaaS, PaaS and SaaS.
What is Infrastructure-as-a-Service? (IaaS)
This most basic cloud computing services model lets you “rent” cloud computing infrastructure from a vendor. This infrastructure could include data storage, servers and virtual machines (VMs), networking tools, computing power or other building blocks for cloud IT.
IaaS provides IT leaders with access to infrastructure resources on-demand. This model lets them avoid the costs and ongoing work of maintaining certain computing resources or entire physical data centers.
The IaaS vendor takes on responsibility for the infrastructure. You keep the responsibility for buying, installing, configuring and maintaining software. This includes operating systems, middleware and applications.
Examples of IaaS
Amazon Web Services (AWS), Microsoft Azure and Google Cloud are commercial providers of IaaS (although they also offer other cloud services). Common use cases for IaaS include:
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Data storage
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Backup and recovery
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Website hosting
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High-performance computing that involves a massive amount of data or variables
What are the advantages of IaaS?
The advantages of IaaS also apply to the other cloud services models.
Cost
IaaS avoids the upfront costs of setting up a data center, including its physical footprint. The IaaS vendor takes on the ongoing costs of provisioning and upgrading data center hardware, firmware and related software.
IaaS is priced on a pay-as-you-go basis and can scale up or down as needed. This helps avoid unneeded over-provisioning of resources. The fixed pricing of IaaS makes budgeting more predictable. The IaaS model also shifts the capital expenditures associated with a data center to operational expenditures, which can be an advantage for some businesses.
Security, business continuity and disaster recovery
Business continuity and disaster recovery are major drivers for businesses moving to the cloud, and are key advantages — along with security — across all cloud services models. IaaS providers apply vast resources to running data centers, applying the latest technology and dedicated staff to provide assurance that your infrastructure is reliable and protected.
The IaaS provider takes on backups, redundancies and defense-in-depth security, and deploys all of this at a level that most businesses would be unable to match on their own. Service level agreements (SLAs) put these assurances into a contract.
Business agility
In addition to being cost effective, the ability to quickly scale resources up or down can increase business agility exponentially when compared to handling a demand spike in-house.
For IaaS, if you have a sudden spike in demand, autoscaling lets you accommodate the surge and will scale back down when needed. This automation is much easier than either provisioning additional in-house resources that may go unused most of the year or taking the time set up new servers.
The Bottom Line for IaaS
IaaS offers a high degree of flexibility and control, but it requires that you have the in-house technical expertise required for installation, configuration and ongoing maintenance of your applications, related operating systems and middleware.
What is Platform-as-a-Service? (PaaS)
Platform-as-a-Service (PaaS) is a model that helps developers across the software development lifecycle to build, test, deliver and manage software applications.
Using a PaaS, developers can build cloud-based apps and powerful, complex cloud software faster and more easily than traditional methods. Like other “-as-a-Service” models, PaaS resources can be purchased on an as-needed basis and are accessed over the Internet.
PaaS includes infrastructure (i.e. IaaS), but adds a development framework, application infrastructure, middleware, container systems like Kubernetes, and other pre-built components, development tools and resources. These features dramatically reduce the amount of coding while making it easier to build sophisticated applications that incorporate advanced technology like analytics or business intelligence.
Examples of PaaS
Vendors that offer PaaS service models include AWS Elastic Beanstalk, Google App Engine, OpenShift and Hyland’s Alfresco Digital Business Platform as a Service.
What are the Advantages of PaaS?
PaaS includes the advantages of IaaS, with added advantages for application developers:
Faster application development
A development framework and prebuilt components make application development and deployment faster and easier.
Rapid innovation
A PaaS platform can make new technology available to developers faster than an in-house environment. New features can be consumed as soon as they become available, and PaaS environments are often optimized to take advantage of advanced technology that developers can use to enhance their applications.
Enhanced development team abilities
A PaaS offering can expand your development team’s capabilities without recruiting and hiring new staff to bring in the required skills.
The Bottom Line for PaaS
A PaaS solution frees developers to focus on creating applications. It can provide tools and access to powerful technology that make it easier to deliver more advanced software, faster.
PaaS has less flexibility than a development environment that uses only IaaS, and its use is narrower. A PaaS solution may support only specific approaches to application development.
What is Software-as-a-Service (SaaS)?
A Software-as-a-Service (SaaS) solution provides everything you need to use a cloud-based software application over the internet. The SaaS provider manages and maintains the software and infrastructure. Users access the software over the internet using a web browser or desktop interface that allows work to continue even when an internet connection is temporarily unavailable.
SaaS typically follows subscription-based pricing and may offer different tiers and price points based on functionality and number of users. Unlike on-premises software, the SaaS provider is the software owner, and the buyer essentially “rents” the software.
Examples of SaaS
SaaS offerings are commonly used in businesses, schools and for personal use to conduct everyday work, such as sending and receiving email, word processing, video conferencing and countless other applications that run via the internet.
Examples of SaaS applications include Office 365, Salesforce and Adobe Creative Cloud. The Hyland Cloud is a SaaS offering.
What are the Pros and Cons of SaaS?
Because SaaS includes infrastructure, it offers the advantages of IaaS — with additional benefits:
Access to sophisticated software
SaaS opens opportunities to use sophisticated software that was once prohibitively expensive — or became prohibitively expensive to maintain as an on-premises deployment. Repeated software upgrades also could be costly, time-consuming and risky. Today, even the most complex and powerful software is available via an internet connection, and software updates are seamless.
Support a distributed, collaborative workforce
Because SaaS solutions are internet-accessible, anyone with access can work from anywhere, anytime. While some SaaS applications are used only with a web browser, many offer an additional desktop version that allows the user to continue working even when they are offline.
The internet accessibility of SaaS also enables better collaboration among users. SaaS lets them work together to craft documents, discuss images or analyze data. They can even do all these things together in real-time.
Security and disaster recovery
In a SaaS model, security and disaster recovery apply to the application, related data and the infrastructure. In an IaaS model only the infrastructure is included.
A SaaS solution can strengthen security with “defense-in-depth.” This approach addresses security at a numerous levels from security policies, to monitoring facilities and online activity, to ensuring software is always current and patched. Backups and redundancies can allow business to continue even when unexpected events impact business facilities or data centers.
The Bottom Line for SaaS
While SaaS doesn’t offer the high degree of control of software managed on-premises, it is becoming increasingly adopted because of its advantages. For organizations with limited IT resources, it may be the only solution for using sophisticated software that would otherwise be too costly and complex to buy and maintain. When choosing a SaaS provider, it is important to understand specifically what your shared responsibilities are, who is responsible for what, and what level of support you can expect. Uptime, data protection and disaster recovery are critical to understand, and all expectations should be built into your contract.
Deciding on a Cloud Application Services Model
No cloud service model is fundamentally better than another — they simply suit different requirements. Whether you choose a SaaS, PaaS or IaaS solution will depend on your organization’s goals, requirements and resources. Regardless of the choice, all three models can help free an organization’s IT team to focus on the core business rather than on IT infrastructure. As is everything that pertains to the cloud, the cloud services models are still evolving.
Hyland in the Cloud
Hyland is a leading content services provider with a range of cloud-based technologies, solutions and services. As our customers migrate their content to the cloud (or launch there), we are with them to make sure their solutions operate at maximum capacity from day one.
Learn about what Hyland does, or read more about Hyland in the cloud:
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