The mainframe is alive and well at the global human resources consulting and outsourcing firm Hewitt Associates, but it’s getting quite a bit of help these days from a Linux-based grid computing platform.

For one application, the grid reduced total computing costs by about 90%, according to Daniel Kaberon, director of computer resource management for Hewitt, based in Lincolnshire, Ill. For another, it reduced the time required to run jobs by as much as 95%.

Kaberon spoke about his experiences with the DataSynapse GridServer platform at the recent Network World IT Roadmap Conference & Expo in Chicago, as well as in a follow-up interview (available here as a Webcast).

Some 2,300 companies use Hewitt Associates consulting services while another 340 companies rely on the firm to administer human resources, healthcare, payroll and retirement programs to millions of their employees and retirees. Hewitt has 24,000 employees in 35 countries.

Hewitt likes its IBM zSeries mainframe for a variety of age-old reasons, Kaberon said, including security, scalability, auditing and high availability, to name a few. “The great joy of having mainframe applications is they can have a lot of compute power, storage, database and transaction processing all in the same place," he said. “It gives you a big pool of resources to do things with a tremendous amount of scale and availability.“

The downside is cost. “For certain applications that don’t exploit those qualities of service, using that compute power is a very expensive way to get things done,“ Kaberon said.

DataSynapse GridServer software lets Hewitt selectively offload some application processing chores from the mainframe to relatively low-cost Linux-based blade servers, then ship the results back to the mainframe. In that fashion, Hewitt maintains all the benefits of the mainframe while dramatically lowering its costs.

Pension app test bed

Hewitt began dabbling with grid computing in 2003, starting with its Pension Calculation Engine application. Hewitt provides pension administration services for many Fortune 500 companies. The pension application enables employees of those firms to calculate their expected benefit payments.

“[Employees] want to know how much would they get per month if they were to retire when they turn 60, or later this afternoon after a terrible bout with their boss,“ Kaberon jokes. The requests come in over the Web and the application collects information about their plan, their hire date and so on, then crunches the numbers to come up with an answer. “That takes a lot of calculation power to do,“ Kaberon said, placing a large CPU cost on the mainframe. Should the individual want to change some parameters — say, if they retire at 65 instead of 60 — the process starts all over.