Linux has made the transition from rebel code to respectable corporate operating system faster than a speeding Usain Bolt.
Just five years ago it would have been a gutsy move for a large enterprise to depend on the open source operating system. It was certainly more risky than “buying IBM.” But today it’s to be found on pretty much all major vendors’ hardware in data centers up and down the country.
Is it ready for the most demanding environments? Certainly.
That’s the experience of Sabre Holdings, the parent company to Travelocity, Lastminute.com, Sabre Travel Network and Sabre Airline Solutions. The company operates the largest travel distribution system in the world, and its customers include ticket buyers, travel agents, travel suppliers, government agencies and large corporations. Sabre’s systems are busy — really, really busy — handling hundreds of millions of transactions a day peaking at a rate of 32,000 transactions per second, according to figures supplied by the company.
More Enterprise Linux
Two years ago much of Sabre’s infrastructure was running HP NonStop high availability systems and Solaris machines running on Sun’s SPARC processors. However Robert Wiseman, the company’s CTO, decided the time was right to make a move to cheaper Intel processors and standardize on Linux. “Basically, we wanted to run on Intel to take advantage of the high speed and low cost of these processors,” says Wiseman. An alternative would have been moving to a Microsoft platform, but that was never seriously considered, he explains. “We looked at Windows but we didn’t want to be vendor specific. If we standardized on Windows and then we found at some time in the future that the Intel x86 was no longer the cheapest chip, we would have been dependent on Microsoft to move the platform to the cheaper chip before we could take advantage of it.”
When Sabre actually benchmarked Red Hat Enterprise Linux (RHEL) running on Intel against Solaris on SPARC, it found quite a difference — to say the least. The Linux/Intel combination was three times faster than the Sun Unix solution, and when both licensing and hardware costs were taken into account it worked out about 90 percent cheaper, according to Wiseman.
As a result, in early 2007, Sabre began to phase out its HP Non-Stop and Solaris systems by making HP blade servers running RHEL on Intel its standard for all new projects and the older systems have been — and still are — being replaced with the new Linux servers as they reach the end of their lives. In total the company now runs over 5000 REHL servers around the world.
The move to Linux and Intel has saved Sabre substantial amounts of money, Wiseman says, but it was only possible because he was convinced that it would prove reliable enough to replace the NonStop and Solaris systems. As things turned out, Red Hat’s Linux has proved rock solid, vindicating his position. “In fact we haven’t had a single outage because of Linux,” says Wiseman. “The only outages we have had are from hardware failures, but because the hardware is so cheap we can have redundancy to overcome that, he says.”
Vendors of closed-source software sometimes claim that the open-source model is not suitable for the creation of enterprise-grade software, questioning whether software written “in the community” can possibly be practical. “How can you rely on it and who are you going to turn to if things go wrong?” is the implication. Aside from the fact that companies like Red Hat stand behind their commercial distributions, Wiseman has discovered that the availability of source code can be a major bonus for organizations such as his with the right programming resources available because they are no longer beholden to another company for patches.
“We run a very demanding environment which at times is carrying out tens of thousands of transactions per second, and we have no scheduled outages,” he explains. “This is really pushing the software to the limits, and in that type of environment software tends to break. The fact is that we do sometimes tend to break our software, and being able to look at the code ourselves and fix it, instead of waiting for a vendor to provide a fix, is a very big benefit to us,” he says.
Linux’s share of data-center server spend grew 10 percent last year (according to research house IDC), and Sabre’s experience goes a long way to explain that statistic: high reliability, 90 percent lower cost and triple the performance. As Linux heads onwards and upwards, this must be food for long and strategic thought for proprietary Unix vendors.