The Next Evolution of Linux on System z

Illustration by Viktor Koen

When the Linux* OS made its initial appearance on the mainframe, the skeptics might have responded, “Really? That’s what x86 boxes are for.” And many of these people chose to run z/OS* on IBM System z* and Linux on Intel* technology-based servers, in the belief that these two OSs couldn’t peacefully co-exist on the same system.

Over time, however, virtualization became commonplace and perceptions changed as more organizations saw the benefits of workload consolidation. Larger organizations were the first to see the light. As they rolled out services supported on a multitude of boxes, their data centers began to bulge at the seams. Administrative overhead grew, licensing costs skyrocketed and energy consumption became more than a footnote on IT budgets.

Together, these and other factors prompted IT managers to reconsider their segregated workload/hardware mindset. They began with light Linux workloads loaded on mainframe partitions to test whether heavy-duty mainframe workloads and lighter-fare Linux operations could, in fact, work well together.

As it turned out, they could, and companies soon began moving more Linux workloads to the mainframe. Now, most mainframe users expect to run some instances of Linux on their big-iron boxes—and for good reason. Not only does this type of consolidation help reduce IT operating costs, but it also allows organizations to take advantage of the security, availability, scalability and manageability of the mainframe platform.


Decisive Factors

“Another decisive factor driving Linux on System z deployments, as noted by customers doing so, is the optimization of Linux to run with System z’s z/VM* virtualization software environment, which makes highly efficient use of the hardware resources available to it,” according to “Enterprise Linux Consolidation and Optimization on IBM System z,” a whitepaper by Jean S. Bozman. “This means that Linux workloads deployed directly onto System z servers or migrated to System z from other platforms support these features, which are important for mission-critical workloads that cannot be interrupted without impacting business continuity.”

Bill Reeder, worldwide sales leader for IT Optimization and Cloud for System z, cites an example of a software as a service (SaaS) vendor that was having issues related to outages on x86 servers. “If the systems went offline, so did its business,” Reeder notes. “As a result, it moved its Linux workloads to the mainframe. Now, its more than 115,000 registered users don’t have to worry about downtime.”

Indeed, in a Forrester Research report, “The Total Economic Impact of IBM System z,” authors Michelle S. Bishop and Jon Erickson remark: “With the drive to maximize cost-efficiency came the need to maintain high levels of availability in an increasingly complex distributed environment. Many organizations realized their existing distributed architecture could not provide high levels of availability as the environment grew.”

In another case, an online U.K. art dealer is moving its workload to the mainframe due to issues related to uptime and software costs. It, too, was running Linux in an x86 environment. But after doing some research, the art dealer decided it might be wise to move Linux instances to the mainframe. Notably, IBM didn’t make a sales call in this case. Instead, the customer contacted IBM.

Jim Utsler, IBM Systems Magazine senior writer, has been covering the technology field for more than a decade. Jim can be reached at

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