In-Depth

A Mainframe First: J2EE Performance Testing for Big Iron Web Apps

Big Blue’s Rational Performance Tester for z/OS isn’t a technology in search of a market—it’s a reflection of market demand, IBM officials say

• By Stephen Swoyer
• 09/13/2005

Just how real is the mainframe resurgence? It’s bona-fide, according to IBM Corp., which last week announced a new J2EE testing and analysis tool for z/OS, called, appropriately enough, Rational Performance Tester for z/OS.

Big Blue claims its newest Rational application testing tool isn’t a technology in search of a market, either. Instead, says Jeff Schuster, a senior manager with IBM Rational, Rational Performance Tester for z/OS was developed to satisfy the requirements of high-end customers who are increasingly deploying workload-intensive J2EE applications on z/OS.

In point of fact, Schuster indicates, it was IBM Global Services (IGS) that first reported pent-up demand for a J2EE performance testing and analysis tool for z/OS. “We’ve been working very closely with Global Services to identify those customers, because [IGS are] the ones that first pushed us in that direction,” he says. “They have a lot of customers that are looking for this type of solution, so it was that need that drove us to build that solution.”

Big Blue’s new Rational Performance Tester for z/OS is based in part on a tool IBM first developed for J2EE application testing in the distributed space (called Rational Performance Testing), where several vendors—including Compuware Corp., Mercury Interactive Corp., and a host of others—market J2EE performance analysis tools. But while J2EE performance testing is old hat in the distributed space, IBM officials say it’s uncharted territory in the z/OS world.

“Specific to stress-testing and testing tools in the mainframe space, yes, Compuware has some tools in that arena, CA has some tools in that area—but those tools are all focused more on the SNA environment. CICS is another example of what these tools are targeting. These tools exist and they’re there and they provide a valuable solution for legacy apps,” he comments. “But what Rational Performance Tester does is actually brings in a new technology, a new solution into the mainframe space that they have not had before.”

No Longer Shooting From the Hip

Absent a tool like Rational Performance Analyzer for z/OS, Schuster claims, organizations must make do with a variety of ad hoc solutions. One such approach, he suggests, is to deploy a Windows or Linux client farm and hammer away at a J2EE applications hosted on zWebSphere. “Previously, the way you would have to do that is to use a bunch of smaller Windows boxes to be able to generate code, but for obvious reasons, it becomes untenable to do that, especially for these very large [workload-intensive] applications,” he says.

To a limited degree, Schuster concedes, most organizations can do application stress-testing on their own. But given the scale of many zWebSphere application deployments—which are designed to support thousands or tens of thousands of concurrent requests—homegrown stress-testing is prohibitively difficult. “But most companies didn’t even do this level of testing in the mainframe environment,” he points out.

“People do a lot of modeling in this world, and they use models of statistical analysis to determine what the capacity of that server would be once it was functioning. So they did that, but that didn’t allow them to actually test the physical application running under load, and didn’t allow them to test for specific vulnerabilities that might be expected under load.”

Enter Rational Performance Analyzer, which lets organizations simulate the effects of thousands or tens of thousands of users hammering away at their zWebSphere applications. By stress-testing in this manner, Schuster argues, developers can identify application-performance and potential security issues before they’re discovered in production.

“For those organizations that have mainframe hardware and have applications running on the mainframe hardware, we’re actually bringing to them a set of tools for stress-testing their [Web] applications in that space,” he says. “Anyone deploying a large Web application server in that space, or a large database application, can use IBM Rational Performance Tester to create a load on that server and have a very accurate idea of how that system is going to respond.”

Rational Performance Tester for z/OS isn’t a mainframe-only play. It can also be used to stress-test Web applications running on Windows, Linux, and Unix systems. One reason organizations might choose to do so, IBM suggests, is to generate loads that can’t easily be simulated on non-mainframe hardware. Schuster says Rational’s mainframe presence should expand over time. He cites the Rational Functional Tester, a tool that IBM delivered last year to test an application’s pages for the accuracy of different activities, such as (for example) online bill-paying and account balance inquiries.

These are just the tip of the iceberg, Schuster claims. “The testing tools that are out there, a lot of them have been around for quite some time. They haven’t been modernized. Although they might work very well, they haven’t been addressing the usability modes, [the developer] who is required to use the tool effectively. [What] Rational has been bringing in is some new tools, based on new technology, that help to refresh this [segment],” he observes.