Date: Wed, 22 Mar 2000 10:55:23 +0100 Subject: Gros cluster a UNM de IBM's Netfinity's sous Linux. Succes a terme de cette strategie predite pour le HPC. From Computergram + UNM to Build Big Linux Supercluster By Timothy Prickett Morgan While vendors, analysts and customers debate the ultimate applicability of Linux to their data center operations, everybody in the high-performance supercomputer community seems to agree that Unix is living on borrowed time in the HPC arena. Conventional Unix-based supercomputers offer higher bandwidth, bigger memory blocks and more reliability than supercomputers based on PC server components, but the combination of lower-price components and open community software is making Linux superclusters not only a viable alternative, but increasingly a preferred one for academic and industrial supercomputing. Today's announcement by the University of New Mexico that it is building a Linux cluster using IBM's Netfinity thin servers that will be the world's fastest Linux HPC box and Number 24 on the Top500 supercomputer list lends credence to the view that Linux will eventually rule HPC and that it won't be too long before the world's fastest supercomputer will be a Linux machine running on IA-64 processors. The Linux cluster being built by UNM, which is nicknamed Los Lobos, is comprised of 256 of the two-way Netfinity 4500R thin servers. Netfinity 4500R thin servers appear to be one and the same as the forthcoming "Illinois" and "Assault" servers that IBM is set to ship in a few weeks (CI No 3,863). Illinois is a 3U, two-way server that offers more I/O capacity in terms of multiple PCI buses as well as more PCI slots, plus more memory capacity and more disk capacity than the current 4000R "Intimidator" thin server. Illinois also includes hot swap disks and various redundant components to increase the availability of individual units. Assault will offer more I/O, memory and disk capacity than Illinois as well as ActivePCI and integrated chipkill memory. Illinois and Assault thin servers are expected to support the latest Intel processors running at 733MHz or even 800MHz. UNM is getting 4500R servers equipped with 733MHz Pentium IIIs, 256 of them, in fact, for a total of 512 processors. Back in December, IBM had said that it was putting together a deal for a 512-node follow-on to UNM's 64-way "Road Runner" cluster that would use four-way Intel PC server motherboards for a total of 2,048 processors (CI No 3,812). Someone got their wires crossed in speaking about it and probably meant that IBM would propose a 512-processor cluster using either two-way or four-way Intel motherboards. The two-way Netfinities thin servers offer a much smaller form factor than the four-way servers, which have memory, disk and I/O capacities that are overkill at least as far as parallel computing is concerned. Processor clock speed and keeping costs low is much more important than having a large number of processors in an SMP configuration because with parallel computing you can always just add more processors. That's why Los Lobos is built using what appears to be the Illinois thin servers. We reckoned last December that a 2,048 processor Linux cluster with 512 nodes would have about 1.2 teraflops of peak number-crunching capacity and about 900 gigaflops running real Fortran and C applications. The 256-node, 512-processor Los Lobos cluster is estimated by IBM to provide about 375 gigaflops of peak power and about 285 gigaflops where the compiler hits the chip. Los Lobos will be configured with 1Tb of disk capacity, 1.5Tb of tape capacity, 512Mb of main memory per Pentium III processor and 256Kb of L2 cache memory per processor. These memory specs are very modest, and that is one of the reasons why the National Science Foundation only had to kick in $1.5m to help build the Los Lobos cluster. The total cost is more than that, and UNM and IBM is not saying what the total price tag for the Linux cluster will be when it goes operational this summer. It will very likely be in the $2.5m range, which comes to about $10,000 per node. Frank Gilfeather, executive director of HPC at the university, says that the real compelling argument for Linux clusters is not just their low cost - which tends to be anywhere from a third to half of the cost of a conventional supercomputer - but the openness of Linux. Researchers in various fields can have Linux running on their desktops, use open community code, tweak it for their needs, test it on a local baby cluster and then run their jobs on the production superclusters like Los Lobos, all without leaving the Linux environment. When you add those two factors together, and multiply it by the fact that university and commercial researchers do not want to specialize in operating systems, interoperability or performance tuning - they just want to run their applications on the fastest computers they can afford - it isn't hard to see that Linux will very likely take over in HPC long before it does in the commercial world at large. The industry lowdown has it that within the next 12 to 18 months, a Linux hypercluster using Intel's IA-64 processors will unseat Intel's ASCI Red (the current number one on the Top 500 list) and IBM's ASCI White (projected to be number one by 2001) supercomputers as the fastest production supercomputer in the world.