While many businesses keep clinging to existing Windows, NetWare, and OS/390 solutions, more and more are turning to Linux clusters for high performance computing (HPC), high availability (HA), and Web farm applications. To get the most out of Linux clusters, however, you need to know the ins-and-outs of installation and maintenance, as well as the best software and hardware configurations for specific types of clustering implementations.
So what exactly is a cluster, anyway? "More than one machine, working cooperatively on one or more tasks," says Sean Dague of the IBM Linux Technology Center.
Linux clusters are "like 1,000,000 ants vs. one elephant," Dague illustrated, speaking during the Linux Boot Camp at the recent PCExpo/TechNYXpo conference in New York City.
Yet despite advantages ranging from speed to cost effectiveness, Linux clusters can be a tough solution to sell, according to some audience members at the boot camp in Manhattan. One IT consultant attending the show said that, after years of trying, he is just now starting to convince some of his customers of the benefits.
"My customers have been willing to adopt Linux — but not Linux clusters."
Over the past month, though, one of his customers, a large insurance firm, has decided to replace its previous Novell NetWare implementation with Linux clusters, instead of Microsoft Windows clusters as originally planned. "The firm could have saved $65,000 in consulting costs if they'd followed my first advice," the consultant said.
Closer than Windows to Unix and NetWare
Linux also bears much closer resemblance to legacy OSes such as Unix and NetWare than Microsoft .NET, some observers say.
One of the IT consultant's insurance firm customers actually tried out Windows clusters for several months before taking the consultant's advice and moving to Linux instead. The flat file database formerly used with NetWare is working much better under a Linux architecture than on Windows.
"Lawyers at the company like to be able to share files without dealing with Windows' proprietary things such as UNC," added the consultant.
Reliability and performance of Linux
Other frequently cited advantages of Linux clusters include reliability, modularity, and fast performance.
The IT consultant told a story about the CEO of another client company that has moved to Linux. When the CEO was about to deliver a presentation at an industry conference, he asked for statistics on the availability of the company's Linux systems. The company chief was astounded to get the answer: "364 days a year."
"Jobs that [would otherwise take us] about a month to complete can now be run in about 10 to 12 hours," says Alex Bogdan, a principal developer at Electro-Optical Sciences (EOS). EOS is now operating a Red Hat Linux-based cancer diagnosis application called MelaFind on PC-based eCluster systems at IBM's "Deep Computing on demand" facility in Poughkeepsie, NY.