Linux on the IBM mainframe

Linux saved the IBM mainframe. No, the mainframe wouldn’t have gone away without Linux; it still handles the vast majority of the commercial world’s transactions and data. The mainframe would have continued beyond our lifetimes as a niche product, unassailable for its security and reliability but not very interesting for much else except its core use case. Linux on the mainframe, which celebrated its tenth anniversary earlier this year, changed all that.

For starters, Linux on z quickly expanded the number of applications you could run on the mainframe. At last count Linux on z essentially doubles the number of applications available for the mainframe platform. But more importantly, these Linux applications make new workloads feasible on the z, things like BI and Web 2.0. Even better, Linux on z will be instrumental in IBM’s push on mainframe computing to the cloud.

Citigroup has become a poster child for both the z196 and Redhat Enterprise Linux v6 (RHEL v6). Citi, reportedly, turned to RHEL v6, the latest rev, to achieve a common global Linux build across the company. Between the z196 and RHEL v6 it has been able to retire a number of one-off infrastructure software products, which saves the bank their associated costs. Along the same lines, it has been able to negotiate enterprise-level agreements for a reduced number of third-party products that can be leveraged across x86 and z hardware platforms. In short, with a common Red Hat Enterprise Linux build, Citi is able to choose the virtualization platform, either z or x86, that best meets its requirements.

Redhat isn’t the only Linux option for the System z. Novell’s SUSE Linux has a following too. In fact, JD Williams, a large UK-based online retailer that has already rolled its new z196 into production runs SUSE Linux on the new machine, where it uses Linux for image serving. Customers shopping on one of its many sites can click on a product and see an image or even a video.

The most intriguing aspect of SUSE Linux is Mono, a .NET application server that runs on Linux on the z. By using SUSE Linux Enterprise Mono Extension, .NET-trained developers can use the .NET application framework to port .NET-based server applications to Linux running on the z. In effect, you could use SUSE Linux with Mono to run what amounts to Windows on the z. If you are curious about Mono, here is the FAQ.

Mono on the z, however, sounds better than it apparently works in practice. DancingDinosaur has spoken with a few z staff at companies that have tried it but never got it working well enough to consider it production ready. Am still looking to speak with a z shop that is doing SUSE Mono for real if you know of any.

IBM has been doing almost everything it can to drive Linux adoption on the z. It slashed the price of the IFL. It also put together a System z Solution Edition for Enterprise Linux bundling the hardware, software, and maintenance at a steeply discounted price.

Still, adoption of Linux on the mainframe seems slow. A large percentage of the biggest z shops, like Citi, have it but many haven’t put it into actual production. Among smaller z shops adoption of Linux on z is low. One smaller z10 shop told me they have Linux on their z10 they still run Cognos on distributed systems. Again, IBM offers numerous ways to entice adoption of Cognos on Linux on z, mainly by cutting price.

At the least, z shops that run Oracle on multiple distributed servers should consolidate those servers on Linux on z. The way software pricing works with assist processors like the IFL, an organization will save a bundle on software licensing alone, making this a no-brainer. Plus you get the reliability, scalability, and security of the z.

Not only is Linux an enterprise-class operating system but it brings worthwhile new workloads to the z. There aren’t a lot of bargains in the mainframe world, but Linux on the z has to be one of them. If you can’t get IBM to entice you with a great deal, you’re not trying very hard.


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2 Responses to “Linux on the IBM mainframe”

  1. CA Drives Linux on the System z « DancingDinosaur Says:

    […] Linux on the System z and now the zEnterprise for a decade. DancingDinosaur has long argued that Linux on z saved the mainframe from becoming niche product, albeit a big, pricey […]

  2. EUROCONTROL Adopts zEnterprise Hybrid Computing « DancingDinosaur Says:

    […] At a recent analyst briefing, IBM reported about 80 zBX sales. Given the thousands of active mainframe shops in the world this represents very slow adoption at best. IBM managers insist adoption takes time, and they point to Linux on z, which took 10 years to surpass adoption by one-third of the mainframe shops. (BTW, DancingDinosaur has long argued that Linux saved the mainframe.) […]

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