Case Study: Echo2 High Availability

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On Saturday morning, September 24, 2005, as Louisiana National Guardsmen distributed bottled water, ice, and food to people whose lives were shattered by Hurricane Rita, the emergency IT staff of Unibill, LLC was in the final stages of an unplanned failover of its business-critical applications to the company's dedicated backup site in Dallas.

Unibill provides a hosted Customer Care and Billing package to several cellular and landline telephone companies on its iSeries Model 810. As one of its mission-critical processes, Unibill's AEGIS/Secure application polls telephone switching equipment for "pay as you go" cellular telephone operators in real time over a VPN link. It downloads call records in near-real time so they can be rated. Then, it decrements the value of each call record from the appropriate prepaid value bucket.

"We are in a business where you have to be live all the time," says Mike Clark, Systems Manager of Unibill. "That's why we located our main production data center in a building that more closely resembles a fortress. Our building is literally made out of stone; we have a 280KVA diesel generator and a UPS that will keep us running for 200 minutes in the event of commercial power loss and until the generator takes the load. Furthermore, we have a fully mirrored high availability hot site backup in Dallas. All of these things made us feel pretty secure."

Late on the evening of Friday, September 23, as the wind picked up, Clark and a few members of his IT team hunkered down in Unibill's data center. As Rita struck the gulf coastline about 30 miles to the south at category-three intensity, the outlook in the data center was still guardedly optimistic. Ten minutes later, Rita thrashed furiously at Unibill's door. Because of severe tree damage and toppled communication towers, telecommunications lines proved to be the Achilles heel for Unibill. Unexpectedly, Unibill began to lose its Internet links to the outside world as connectivity was lost to the ISP.

In retrospect, Clark realizes that he should have done a role swap to the hot site (enable the backup system to take control of applications) as soon as the storm threatened to hit land somewhere along the upper Texas and southern Louisiana coastlines. Unfortunately, as midnight approached on Friday, the VPN connection between his iSeries box and the outside world was gone. According to Clark, "The lesson we learned was to do the role swap sooner. We were confident of our building and our emergency backup systems, but there are so many other things that can fail over which we have no control."

As it happened, Unibill had licensed Echo2 from premier high availability software vendor iTera, Inc. in August 2005. As a final test of the Echo2 installation process, Unibill had scheduled a role swap test for October, but Rita was impatient and struck in September. When the VPN links failed early Saturday morning, Unibill was forced to do an emergency role swap (commonly called a "failover") and immediately called iTera. Unibill had dispatched its offsite disaster recovery team to its Dallas backup site, hoping the team would not be needed.

When Unibill staff arrived at the backup site in the early hours of Saturday morning, iTera guided them through the necessary system audits on the iSeries Model 520 backup machine. Because Unibill was relatively new to Echo2, an iTera technician stayed on the telephone throughout the whole process. "I was very pleased with their commitment," says Clark. "They said they were going to support us, and they were there whenever we needed them." Together, Clark and iTera's support staff found that the backup machine had committed every transaction up to the point where the communication lines had failed. After the failover had been completed, all that remained was to have Unibill's customers point their systems to the IP address for the backup 520 in Dallas.

With Echo2, replication latency is negligible because it exploits the capabilities of the i5/OS remote journaling capabilities. Prior to deploying Echo2, Unibill tried to use another HA product, but because Unibill's AEGIS/Secure's application dynamically creates and deletes files so quickly, replication latency times grew to an unacceptable point.

"I don't want to sound melodramatic, but when I think about what the business losses would have been without the hot site, I tremble," says Clark. "Our customers require 24x7 uptime. Quite frankly, if I'm not able to ensure continuous uptime, my customers will look elsewhere for their billing needs."

While waiting for electrical and telecommunication services to be restored at the primary location in Lake Charles, Louisiana, Unibill continued to run on the backup machine in Dallas for a little over four weeks. "Though our customers were impacted as a result of the unplanned failover, they were nonetheless able to continue with their mission-critical processes on the HA box just like nothing had ever happened," says Clark. Once the production site became available again in Lake Charles, Unibill was able to move operations back via a planned role swap.

Today, Clark is well-versed in the operation of Echo2. "I find it to be very straightforward and easy to use. Echo2 runs on top of i5/OS and utilizes many of its functions to do its job. iTera makes it easy to maintain the Echo2 software with an automated PTF system. And I like the fact that I don't have to bring the entire Echo2 system down to apply them."

In the end, the chaotic situation that Unibill was thrown into would have been much worse without Echo2. As a result of its experience with Hurricane Rita, Unibill has made quite a few changes in how it runs its shop. According to Clark, as a new hurricane season approaches, "I am confident that as far as Echo2 is concerned, we have the right technology in place, and we are well-prepared for whatever comes our way."

Robert Gast is a regular contributor to MC Showcase and has reported on technology and business since 1986. He is the managing partner of Chicago area-based Evant Group and can be reached at This email address is being protected from spambots. You need JavaScript enabled to view it..

iTera, Inc. is a leading developer and integrator of high availability and continuous availability solutions for System i. iTera's products have been implemented at hundreds of organizations around the world.

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iTera, Inc.
5250 Wiley Post Way, Suite 500
Salt Lake City, UT 84116
Tel: 800.957.4511 (USA and Canada), 801.799.0300 (other countries)
Web: www.iterainc.com
Email: This email address is being protected from spambots. You need JavaScript enabled to view it.

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