On The Day London Blows a Fuse

31 May 2007

For years now, the Tastes Great, Less Filling argument pervading the high-performance computing debate has been Scaling Up, Scaling Out. I’m not sure who penned it originally, but I remember first hearing it back in 1999 while Microsoft was trying to position Windows as a compelling enterprise server platform in the face of multi-way Big Iron from Sun, HP, and others, especially during a period where dual processor Intel configurations were exorbitantly expensive. The Scaling Out story warned of the high costs, low ROI of Scaling Up and beckoned with perfectly elastic scalability. Scaling Up promised better performance potential for particularly ravenous applications and a less ungainly programming and administration model.

Even though, just like that old Miller Lite commercial, the argument ultimately had much more to do with politics and economics than it did with high-performance computing, it still continues to have legs. Over the last five years, just as Scaling Out had seemingly all but usurped the spotlight, the silent multicore revolution has helped Scaling Up elbow its way back to the stage. Scaled-out grids are secretly scaling back up in the natural course of IT departments undergoing periodic server upgrades. The current pricing structure of server hardware is compelling enterprises to specify 64-bit multi-core systems, even though a majority of enterprises have only 32-bit serial applications to run on them. Enterprise grids are getting both bigger and beefier. And though the argument between Scaling Up and Scaling Out lives on and remains an amusing debate for well-heeled parallelogians and gridmakers, the real issues affecting high-performance scalability are seeping out elsewhere.

Earlier this week, I was speaking with Jeff Wierer, Senior Product Manager on the Microsoft High-Performance Computing. He had recently been in London for a Compute Cluster Server User Group Meeting, and the scalability issue on everyone’s mind was physical infrastructure. Specifically, electrical power.

As many of you may already know, London is moving up fast as a world financial capital. Lab49‘s London office has been rained upon with fascinating projects from key financial services customers demanding algorithmic trading, computational finance, real-time data visualization, and high-performance computing. London’s financial institutions have been bulking up their computing horsepower and looking ahead to rich times. Unfortunatley, there’s one little snag.

Jeff told me that some of his customers in London have heard anecdotal reports that the National Grid in the UK is either unable or unwilling to provide the additional physical infrastructure required to support the concentration of power demand coming from the burgeoning financial center in the city. Short of ripping out and starting over, the National Grid may be stuck advising its customers to be happy with the power they got (despite ominous blackouts).

While I haven’t been able to find independent confirmation of this yet, it seems entirely possible given the recent power shortages of East Coast, West Coast and Europe at large, as well as the privatization of European electrical distribution that limited the amount of capital investment available to upgrade power infrastructure. (There are no bigger pockets than the pockets of Big Government…)

In the face of massive metropolitan and regional power crises, the argument between Scaling Up or Scaling Out is irrelevant (and rather pedantic, in my opinion). The real issue is between Scaling In and Scaling Abroad. And like Tastes Great, Less Filling, it really isn’t a debate at all because both are ultimately necessary ingredients of truly scalable architectures.

Scaling In is about putting hardware on a power diet. Let’s just assume that our cores are running at 100%, 100% of the time. Fun power management ideas like Intel SpeedStep, hard drive spindown, or monitor sleeping that reduce power consumption for workstations and laptops aren’t going to bail out institutional data centers. That will require new, more efficient processors and cooling systems, better rack and blade designs, distributed flash-based memories, and a slew of as yet unimagined inventions that software engineers can’t help out with even if they wanted to.

Scaling Abroad is about scaling out to multiple geographical locations. This is commonly a notion attributed to high-availability, business continuity, and disaster recovery, but it’s clearly also a scalability issue now, particularly at the scale of the largest grids (for example, Amazon, Google, and Microsoft). If Google housed all of its computing power in Mountain View, the Governator would come down and force Larry Page and Sergey Brin spelunk through Baja to search for the blown fuse that fritzed California.

At one point during my tenure at Ellington Management Group, air-conditioning and server airflow were the biggest obstacles to growing our cluster. As our server density grew from workstations to rackmount servers, from single processors machines to dual-proc with Hyper-Threading, our server room became a sauna. At first, we bought a bunch of digital thermometers, stuck them around the server room with double-sided type, and made rounds periodically to check that there were no dangerous hot-spots. After we missed a couple rounds over a weekend and carbonized some some silicon, we hooked up SNMP monitors to the built-in motherboard and case thermometers and bought a slew of fans and portable air conditioning units. We ultimately did the right thing and upgraded the HVAC, but not without having to do reconstructive surgery on our office space since our office had neither adequate amperage or ducting/venting to handle an appropriately sized cooler.

Seemed like a tough problem at the time.

Seems quaint now.


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