Robert Wiseman, Sabre's chief technology officer, said the Southlake, Texas-based company began using Red Hat and other open source software in 2004. Red Hat now runs mission-critical online systems that collectively process as many as 32,000 transactions per second from three data centers in Tulsa, Okla., and one in Texas, he said.
The primary motive for moving to open source was the ability to access the code, he said. With transaction volumes as high as Sabre's, even small inefficiencies or errors in the code can slow down servers significantly, reducing overall capacity, he said. The IT staff needs to fix problems on the fly without waiting for vendor support, Wiseman said.
"Vendors promise support, but they can't [at our size], so it's important that we be able to fix problems ourselves," Wiseman said. "The system had to be resilient."
Sabre also adopted open source for other portions of the software stack, including Apache, ServiceMix, Tomcat and MySQL, he said.Going with RHEL 5
When Sabre began to move from proprietary systems, the company evaluated other open source operating systems including Novell's SUSE Linux Enterprise but concluded that Novell was not as "mature" or respected as it is today and decided Red Hat was a more "proven" option, he said.
The Red Hat rollout began on smaller systems initially and then extended throughout the organization, Wiseman said. During the conversion, Sabre protected itself from problems or glitches by building a performance testing lab where all applications were run on RHEL before going into production, Wiseman said. With 10,000 servers, a 10% drop in efficiency because of application code makes a big impact, he said.
For Sabre, Red Hat proved to be "a good bet," Wiseman said. "It has horizontal and vertical scalability and massive redundancy. It's the right way to architect solutions for optimal performance and uptime."
Cost is another major advantage of open source, he said. The switch from proprietary hardware and software to x86 boxes and open source software is 90% less than the cost of comparable RISC processors running Unix, he said. And the performance is three times faster, he added..
As for other IT initiatives, Sabre has also experimented in its test lab with virtualization using VMware and has begun to consider moving virtualization into a few production areas, Wiseman said. The ongoing evaluation of virtualization is part of an overall effort to consolidate and automate functions such as server monitoring and provisioning to reduce human error, he said.
"Humans are the biggest reason for problems," he said, citing the fallibility of programs and operators. "We need to simplify and automate as much as possible and take humans out of the mix. We'll be looking at data center consolidation as well."