Unobtrusive power
Compute power means CPUs, CPUs mean heat and heat generally means noise. To quiet things down, developers of deskside HPC systems increasingly turn to liquid cooling, as Paul Schreier discovers
A
s a rule, we don’t like ‘idle cycles’, whether queuing up at the supermarket, sitting in a traffic jam or waiting for time on the
department server. Tis is even more the case today where there is a constant push to get results faster. We do have the benefit of some impressive compute resources at our disposal, but there is a lot of competition for these departmental or company resources and it’s generally necessary to queue up to use them. Tis is what makes deskside HPC so
attractive; it’s always at our disposal for immediate use. It might not have the full horsepower of corporate servers with their hundreds or even thousands of cores, but these machines have become so powerful that they can accomplish many of those tasks we are impatiently waiting to get done. For instance, a soſtware developer might want to have a dedicated system for writing and testing code. Or it might be preferable to create a very large simulation problem’s geometry and other settings before submitting the job to a cluster for running the solver, the most compute-intensive part of the project. Deskside HPC, what we might consider HPC
outside of the data centre, has its own special requirements. Such a system must be physically small enough to sit unobtrusively next to a desk or perhaps in a printer room. It must run on power from standard office sockets. And in an office environment, it must be quiet. Tat last point can be difficult to achieve because of contradictory demands. On the one hand, we want more and increasingly powerful processors in our systems. Tat, in turn, means more heat is generated and this heat must be removed. In many cases this is done with fans, but if they are
16 SCIENTIFIC COMPUTING WORLD
too loud, these systems won’t be welcome. In the deskside HPC domain, it’s also
important to make the distinction between a ‘personal cluster’ and a workstation. Today’s workstations might have single or dual processors and perhaps 16 or more cores, but there are no provisions to have the cores work together as in a cluster. Further, scientists and engineers sometimes hit the limits of workstation performance and need flexibility and headroom, and they turn to a personal cluster. Tey can use the cluster’s many more cores to work on one big job or launch multiple jobs and then combine the results.
Market shakeout Interestingly, you generally won’t find deskside clusters from the traditional big-name HPC suppliers; the market doesn’t yet seem to be big enough to warrant setting up a product line in this area. For instance, in 2008 Cray brought deskside clusters into the limelight when it introduced the CX1, which supported from one to four blades, including a GPU blade. Since then, however, this product has been taken off the market. Some insights in this regard come from Jeffrey Cachat, now director of global channel sales and business development at Ciara Technologies, but who was previously the program manager for the CX1 at Cray. ‘Back then, Cray and Ciara entered into
a partnership where Cray took the base technology from Ciara and developed the CX1,’ he says. ‘Tey tried it for several years and while they learned a great deal about this market, they felt there were better business opportunities with more appropriate margins to focus on.’ Cray has meanwhile launched a midrange initiative with supercomputers starting at $200,000; these XE6m and XK6m systems target the market segments and customers previously served by the CX line. Agreeing with Ciara’s assessment and adding
some further thoughts is Oliver Tennert, director of Technology Management and HPC Solutions at Transtec, which builds and also resells workstations and HPC deskside clusters. Among the products it marketed was the CX1, but it was not at all successful for Transtec. ‘We initially had lots of interest in the concept, but there were three major things that held back sales,’ Tennert explains. ‘One was noise. Even with efforts at noise reduction, the box was as loud as a vacuum cleaner, which discouraged its use in an office
as intended. Second was the cabling on the rear of the unit, which was somewhat disorganised and not at all straightforward. Tird, and most important, was price. Cray essentially took the Ciara unit and added a heſty mark-up, which customers balked at.’ Cray isn’t alone in dropping out of deskside
clusters. SGI has pulled back on its marketing of the Octagon III, which holds 120 cores and nearly 2TB of memory in a pedestal format. Te Octane III was developed by SGI, but the company is no longer manufacturing new units; if a customer wishes to buy one, it comes from the company’s Remarketed Products Group. Tese are units SGI has purchased back from customers and is reselling through this division. Why this move? Te company now feels there is only a small niche market for semi-powerful desktop HPCs like the Octane III. It appears to them that most end-user needs in this segment are satisfied initially by high-performance desktop units available from the larger PC manufacturers at low prices, and then when this no longer gives them the performance they need, individuals leapfrog to a departmental cluster. Tis could also be a reflection of how organisational budgets are broken down.
Big players drop out, niche players pick up the ball ‘Te deskside cluster is definitely a niche product,’ Ciara’s Cachat comments, ‘but it’s big enough to be interesting for a smaller company such as ours.’ Tat company has now introduced the third generation of its product, which Transtec’s Tennert feels has solved the three
Representing the third generation of deskside clusters, the Nexxus C from Ciara solves the problems that plagued earlier models
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