Posted: 29 Oct. 2020 5 min. read

Cloud or mainframe? We asked. Most are taking a third path

A blog post by Dave Knight, solution architect and IBM Alliance Cloud lead, and Bob Miller, solution architect and IBM Alliance Legacy Transformation lead.

It’s human nature to define ourselves by our choices, and the world of technology is no exception. In fact, maybe it’s the rule in technology: Thou must have an opinion on every software, hardware, and strategy choice.

Staking out your territory also has a practical advantage: In an environment in which we have more choices available to us than we could possibly sort through, choosing a technology “side” automatically eliminates a lot of time-consuming choices. To use a simple example, once we choose a smartphone, we don’t have to keep track of what’s new with competing devices designed for other platforms.

A similar dynamic dominates the ongoing cloud-versus-mainframe debate: In IT, you’re either a cloud person or a mainframe person. We should know. For years, one of us (Dave) has been the cloud guy—the person pulled into meetings to advocate for cloud strategies and technologies. The other of us (Bob) has been the mainframe guy. But after years of seeing and actively participating in the same debates time after time, we realized that our own positions had become more nuanced in our everyday work. We realized that mainframes have a role to play in even the most aggressive cloud-driven strategies, and vice versa. In most scenarios, it’s not either/or, it’s and—a hybrid model.

Cloud versus mainframe: What’s happening in the real world

We were happy to see a nuanced approach reflected in our recent survey of more than 250 senior business and IT leaders (90 percent were director level and above) across five major industries, who signaled that, in practice, cloud versus mainframe isn’t an either/or proposition. They see roles for both in the same strategy, even as the media and many technology providers suggest that the widespread embrace of cloud solutions is a step away from mainframes. In this view, widespread cloud adoption is setting the stage for a full “cutting of the cord” with mainframes in the near future.

Ninety-one percent of survey respondents identified expanding their mainframe footprints as a moderate or critical priority in the next 12 months. Seventy-four percent said they “believe the mainframe has long-term viability as a strategic platform for [their] organizations.”1 Those are big, impossible-to-ignore numbers, suggesting that not only is the mainframe not being replaced as a critical component of IT infrastructure, but in some cases, it is also experiencing a resurgence. If anything, cloud and mainframe may be locked in one another’s orbits in ways that help both.

Models for coexisting

It’s one thing for IT and business leaders to say they’re committed to both mainframe and cloud technologies. But how are they actually putting them to work together in practice? While there are a wide range of hybrid models, we see most fitting into two broad categories:

  • Integration in place: Aligning with existing applications. Think of this as the mainframe keeping up with adjacent advances in technology, rather than new innovation.
  • Innovation at the edge: Developing and integrating new and emerging capabilities into the mainframe. Think of this as net-new innovation, building on data held in the mainframe.

We’re seeing a growing number of organizations take advantage of new and emerging cloud capabilities while retaining the strengths inherent to mainframes. The transportation industry offers clear examples of both. Airlines are famously dependent on their data, which is held in mainframes. Whether keeping track of customers’ progression from gold to platinum status, managing complex and highly regulated maintenance data on their fleet of jets, running reservations for millions of passengers around the world, or any number of other massively data-intensive functions, all roads lead back to their mainframes.

The stakes are high: If an airline’s mainframes are compromised, its entire business can be brought to its knees in moments. In a high-profile case several years ago, a fire at one airline’s technology command center led to the failure of a significant portion of its servers, immediately causing the cancellation of thousands of flights.

Integration in place

When this same airline looked to create a new app for customers, allowing them to better manage their membership, loyalty, and points program, it chose an “integrate-in-place” model, avoiding the risk of compromised access to mainframe data. Instead, it was able to integrate with an external rules engine to manage core program elements, draw from data held on the mainframe, and take advantage of new cloud-based capabilities. The result was a dramatically improved customer experience, but not an entirely new one. The core offering (the loyalty program) remained the same, even as rules and functionality were changed and cloud capabilities were introduced to better meet customer needs.

Innovation at the edge

By contrast, a travel app that aggregates travel information, allowing travelers to organize, manage, and share their plans simply by forwarding trip data such as reservation confirmation emails, is an example of “innovation at the edge.” The service can also draw from data held on mainframes, such as changes in flight arrival and departure times, while also using data from other sources to deliver new functionality that is largely managed and delivered on the cloud. This app doesn’t replace or improve existing capabilities, it delivers new innovation to consumers that relies on both cloud technology and data residing on mainframes, giving them the convenience of a single resource for managing their travel plans that is constantly, automatically updated.

Outlook ahead: More hybrid cloud-mainframe strategies

These are the types of practical hybrid innovations we’re bound to see more of in coming years, across industries. Rather than taking a solely cloud- or mainframe-based approach, these strategies take advantage of the strengths of each, giving IT leaders greater flexibility as they rise to meet new challenges, opportunities, and risks.

If you pursue a hybrid model, this survey shows you’ll be in good company. The best way to get started is to decide on an approach that matches your business needs and opportunities and accounts for existing IT infrastructure investments. Then take action, because the survey also reveals that your peers are already beginning to place their bets. Those that can harness these new and existing capabilities together are likely to have the upper hand, no matter what the business environment throws at us next.


1 Base: 261 business and IT decision-makers with authority or influence over mainframe decisions. Source: A commissioned study conducted by Forrester Consulting on behalf of Deloitte Consulting LLP, June 2020.

Interested in exploring more on cloud?

Get in touch

David Linthicum

David Linthicum

Managing Director | Chief Cloud Strategy Officer

As the chief cloud strategy officer for Deloitte Consulting LLP, David is responsible for building innovative technologies that help clients operate more efficiently while delivering strategies that enable them to disrupt their markets. David is widely respected as a visionary in cloud computing—he was recently named the number one cloud influencer in a report by Apollo Research. For more than 20 years, he has inspired corporations and start-ups to innovate and use resources more productively. As the author of more than 13 books and 5,000 articles, David’s thought leadership has appeared in InfoWorld, Wall Street Journal, Forbes, NPR, Gigaom, and Prior to joining Deloitte, David served as senior vice president at Cloud Technology Partners, where he grew the practice into a major force in the cloud computing market. Previously, he led Blue Mountain Labs, helping organizations find value in cloud and other emerging technologies. He is a graduate of George Mason University.