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What Data Center Designers Can Learn From Legos
1sockchuck writes "It takes most companies at least a year to build a new data center. Digital Realty Trust says it can build a new data center in just 20 weeks using standard designs and modular components that can be assembled on site. The company equates its 'building blocks' approach to data centers to building with Legos — albeit with customized parts (i.e. the Millennium Falcon Lego kit). Microsoft is taking a similar approach, packaging generators, switchgear and UPS units into pre-assembled components for rapid assembly. Is this the future of data center design?"
The plural of "lego" is "lego".
I saw the "legonotlegos" tag on this story. Anyone who has read the paper materials that come with Lego sets knows the language about calling them "Lego(tm) bricks" not "Legos." Yes, the Lego company feels they have to write that in their products, because they have to protect the trademark in order to keep trademark protection in many world markets. However, that does not mean that regular people must actually follow that usage. You wanna call 'em Legos? Go ahead. You want to be the ten millionth middle-manager who tries to explain a business model or operational strategy using toy blocks of a certain name? Go ahead. The metaphor is already cliched, but go ahead. Just like Oreos (not Oreo(tm) cookies), or Kleenexes (not Kleenex(tm) brand facial tissues), people should not feel constrained in how they phrase popular culture references.
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I learned that given a large enough supply of Lego bricks, their flaws become readily apparent. We owned a day care centre, so I had literally twenty pounds or more Lego bricks at my disposal (after hours and then after we sold the centre).
Legos are heavily dependent on gravity, the gripping power of a brick is impressive (especially if they are new), but torque is more impressive. There is a limit to how far you can build a Lego ledge, and that includes shoring it up with Lego bracing (diagonal Lego bracing is more susceptible to torque). The torque doesn't apply well to a brick that's designed for straight down pressure.
Legos are heavily bound by gravity. The compressive forces of the walls provide grip. In my attempts to rebuild cathedral wall structures, the compression could not be balanced between the flying buttresses and the inner walls, so the buttresses mainly provided a stabilizing effect. The problem was that at about five or so feet, the bottom bricks would not hold because the weight of the bricks above expanded the plastic enough to negate the brick's grip.
Legos provide little resistance to upward pressure (by design this is how you release them, to a degree). This means that as structures sway, you effectively reduce the gripping power of some connection within the structure. This is the equivalent to stress related failure. A larger Lego structure must be glued or it will fail due to these internal forces.
Finally if you attempt to fix some of these issues by sandwiching critical joints, you add mass, which compounds the problem in other joints. Shoring up those eventually just increases the number of locations where failure could occur and statistics steps in and assures at least one failure, somewhere.
I won't even go into the issues with worn bricks, because those are obvious.
Few data centres expand to the size of our largest data centres, but by "designing like Lego" we will simplify things. The danger is that we might standardize on an architecture that has built-in limits. The architecture we currently have isn't as clean in vision as a Lego brick, but it already scales better than the Lego brick, even if it needs to do so by the default structure being slightly less elegant.
These Lego data centre visionaries have the right goal, making it simple, but they might be going about it in the wrong way. I've never heard a rational argument detailing how Lego bricks and data centre components are the same, so this might turn out to be a bad analogy implemented in hardware. Time will tell, but the centres we currently have did not come as the result of people deliberately trying to make data centres more complex.