AmNet Ditches Intel Server Farm for iSeries Scalability

by Alex Woodie

Randy Myres' story about the travails of running an Intel-based server farm are not unusual. Frequent crashes, memory leaks, and troublesome integration drove the chief information officer to check the state of American Mortgage Network's xSeries servers at 1:00 many mornings. But now that the quickly growing wholesale mortgage bank has moved its core lending, e-mail, and Web server applications to a three-way iSeries Model 825, AmNet has room to grow and Myres is sleeping much better.

From its headquarters in San Diego, AmNet manages a wholesale loan business that wrote $10.2 billion in loans last year. The company has 700 employees, spread across 23 offices in 15 states, and by the end of the 2004 it expects to grow to 30 offices.

Several years ago, the company moved its proprietary banking application, which handles everything from loan origination to customer service, from a mainframe to an Intel-based server, running OS/2. This CICS application, which was written in COBOL, ran well enough for the company while it was on the small side. But as the company grew, the group of four networked two-way xSeries servers simply wasn't up to the task, says Myres, chief information officer and senior vice president at the company.

In addition to the four xSeries running the CICS transactions, AmNet had four other two-way xSeries servers running Windows: two each to run the company's e-mail and Web serving applications. Myres says that getting the OS/2- and the Windows-based applications to talk to each other was difficult. "IBM is going away from OS/2, and Microsoft does everything it can to make sure OS/2 doesn't work with Windows," he says.

As AmNet grew, and these applications required more horsepower, the company seriously questioned its Intel strategy. "We could have kept adding servers, adding capacity, but we got to the point where we didn't want to do it," says Myres, who would routinely reboot the xSeries servers every three days to clear memory leaks. "It was too unreliable, and it didn't have the power we needed."

Myres remembered his work with the old mainframes with fondness. "In the mainframe environment, we could scale up the processing horsepower by paying additional money. I wanted to get to that [level of] capacity and reliability," he says. "I wanted to get back to a mainframe platform. I just wanted to get back to stability and scalability."

The company began assessing which platforms it could move to. At that point, the company wanted to remain an IBM shop, and the AIX/pSeries and OS/400/iSeries platforms were the main contenders. Myres had some experience with an AS/400, used for reporting at an old company he worked for, and he appreciated its mainframe-like qualities of reliability and scalability. The company's outside consultant, Advanced Systems Group, supported Myres' decision to move to the iSeries.

In early 2003, AmNet began the move into its new iSeries Model 825, which shipped with three Power4 processors turned on and three processors turned off, a mainframe-like feature called capacity upgrade on demand (CUoD) in eServer parlance. The company used another mainframe-like feature in OS/400 known logical partitioning (LPAR) to carve out some dedicated processor resources for its Domino environment, which would provide e-mail and Web services for AmNet. Then the company installed its COBOL-based CICS loan application in another partition. (Myres says the port from IBM's OS/2 CICS environment to OS/400 CICS went "very, very smooth. . .just a few little gotchas.") The company also installed one Windows-based Integrated xSeries Server card in the Model 825 to provide Blackberry mobile e-mail service to employees.

When the iSeries went live on September 19, its mainframe-like qualities quickly shone through. In benchmark tests of AmNet's nightly batch processing, Myres found the iSeries several orders of magnitude faster than its Intel server farm. With eight Intel processors across four xSeries servers dedicated to the batch run, AmNet could complete its processing in eight hours, Myres says. With the equivalent workload running on 0.9 of a Power4 processor (the fraction of a whole processor the result of logical partitioning), the processing time was cut to one hour, he says. In rough comparison, this means AmNet's iSeries server with 1/8 fewer dedicated processors was doing the same work as the xSeries servers, but doing it eight times faster--roughly a per-processor improvement of 64 times. Admittedly, this is not an apples-to-apples comparison that can be extrapolated to other environments, especially concerning the fact that a 64-bit Power4 processor costs several times more than a 32-bit Pentium. But it demonstrates the power of the iSeries on this particular workload.

Myres attributes this exceptional performance improvement to the integrated nature of the iSeries. With the networked xSeries setup, the Intel processors were never working near maximum capacity. Instead, there was a severe bottleneck in the network. Moving the workload to the Power4 environment eliminated that network bottleneck and greatly improved AmNet's processor resources. With the iSeries' high-speed Virtual LAN connecting logical partitions, and its CUoD capabilities, AmNet has plenty of room to grow.

AmNet's employees are also happy with the new server. Screen response time has greatly improved with the Model 825, Myres reports, and he's no longer considering hiring nightly operators to babysit the xSeries servers. "Its amazing. You come in every day, and things are running just fine," he says. "I used to have to get up at 1:00 every morning and check the servers. Now it just purrs. That's the thing that's so terrific about it; it's just so stable. I don't even check it. It pages the person on call if something goes wrong. But nobody gets a call. Well, almost."

In the future, AmNet will be looking to start programming in Java and using IBM's WebSphere to host its Web applications. The company is also considering using Linux.