Moving to mainframe can be cheaper than sticking with VMware: Gartner

VMware users considering a new home might find it cheaper to move to an IBM mainframe than adopting Broadcom's new licenses, according to Gartner Vice President Analyst Alessandro Galimberti.

Speaking to The Register to discuss the analyst firm's mid-April publication, "The State of the IBM Mainframe in 2026," Galimberti said some buyers in many fields are comparing mainframes to modern environments and deciding Big Blue's big iron comes out ahead.

"I can build a multi-region cloud application, but things like data synchronization and high availability are things I need to build into application logic," he said. "The mainframe has that in the platform, which shields developers from complexity."

He also thinks mainframes are ideally suited to workloads that need many years of transactional consistency and backward-compatibility.

That said, Galimberti doesn't recommend the mainframe for all applications. He said mission-critical applications that are unlikely to change much for a decade are best-suited to the machines, as are Linux applications because the open source OS runs on IBM's hardware.

IBM also offers the z/VM hypervisor, which he says can make Linux "even better and more enterprise-ready."

Which is why Galimberti thinks IBM's ecosystem is attractive to VMware users, especially those who operate a fleet of 500 to 700 Linux VMs.

Galimberti said he has seen "multiple business cases" in which moving from VMware to IBM makes sense under Broadcom's policy of requiring customers to buy its full Cloud Foundation private cloud stack. The analyst said he was surprised those business cases make sense, but insists a mainframe makes sense "under some circumstances."

AI is another workload Galimberti thinks some users will find works well on mainframes, because IBM recently upgraded its Spyre accelerators

The analyst says items like Spyre show that IBM continues to invest and innovate, and that the mainframe "is not a stale platform."

Galimberti said the idea that mainframes were a dead end has been around for decades and was justifiable at some moments in history. But he also feels the idea was oversold by consultants who promoted migrations away from mainframes as sure-fire winners - but under-estimated the complexity of a move.

"Global system integrators were always against the mainframe and encouraged migrations," he said. "Now they are halting the mainframe exit, probably because the number of failures they had were more than their successes."

The firm now advises assuming that by 2030, 75 percent of vendors offering mainframe exit services operating in the "mainframe exit" market will either change their businesses or vanish, and suggests that only 10 percent of mainframe users will want out by 2030.

Which is not to say mainframes are perfect or easy to live with. Galimberti noted that few third-party software developers support mainframes, and those that do understand the potential to hike prices.

Committing to mainframes therefore means planning "to spend time negotiating price and renewal protections, rather than prioritizing the business value these solutions can deliver."

Another downside is that mainframes pose clear lock-in risk, so users may hold back on useful customizations out of fear they make it harder to extricate themselves from the platform.

Access to skills remains an issue, too, as kids these days mostly don't contemplate a career working with big iron. Galimberti sees more service providers investing in their mainframe programs, which might help. So does the availability of Linux.

The analyst thinks the mainframe will be around for some time to come, because IBM is "very engineering-focussed" and "engages with customers who are hyper-conservative" - then just creates the products they want. ®