Moving into Mainframe Linux

Computerworld - Mainframe Linux can boost application uptime and reduce support costs. But users and analysts recommend acting carefully when choosing which applications to move to the open-source operating system and when training staff in the required skills.
The attraction of Linux on the mainframe isn't so much the low cost of licensing Linux or the fact that users can modify it and rely on a community of developers to fix bugs, users say. Instead, the big draw is the ability to combine Linux with the mainframe's proven reliability, speed and management tools to drive down the cost of running critical applications.
"We're not interested in just getting the least expensive thing on the market," says Randy Lengyel, senior vice president of MIS at Wisconsin Physicians Service Insurance Corp. (WPS), a health insurer in Madison, Wis. "We want something that is reliable, functional and has great customer service from the [vendor]."
Hitting the Sweet Spot
The sweet spot for mainframe Linux today is server consolidation -- replacing dozens or even hundreds of separate Intel-based Linux or Windows servers with a partition on the mainframe that dedicates a single processor, memory and other system sources to running Linux.
WPS created a virtual Linux server running on one 250-MIPS processor that was available within an IBM eServer zSeries 900 mainframe and did it at 40% of the cost of ordering, installing and configuring a new Intel-based server, says Lengyel.
A virtual server can be created within two to three minutes and deliver as much as nine times the throughput of a stand-alone server, he says. WPS, a longtime mainframe user, was drawn to running Linux on the mainframe as a way to leverage the mainframe's reliability and to keep support costs low.
The instability of its Windows NT servers was one reason why recreational vehicle manufacturer Winnebago Industries Inc. implemented Dallas-based Bynari Inc.'s InsightServer groupware application for Linux on an IBM zSeries mainframe.
Dave Ennen, technical support manager at the Forest City, Iowa-based company, says he had to reboot his Windows NT servers once a week in an effort to improve their stability. But "on the mainframe, everything is geared to staying up 24 hours a day, seven days a week," he says.
Winnebago already had a mainframe (an IBM S/390 Multiprise 3000 Enterprise Server) and a staff skilled in IBM's z/VM, an operating system that can divide each partition in a mainframe into multiple software-based virtual machines, each running its own operating system and applications.
Rather than go through the expense of training