4 ms·

I've heard of some large companies that run their data centers hot. Cheaper to have a slightly higher failure rate, or have the computers throttle their clock

by JJMcJ 4y ago

I've heard of some large companies that run their data centers hot. Cheaper to have a slightly higher failure rate, or have the computers throttle their clock speed, than to pay for extra air conditioning.

klysm 4y ago
Hard to do the math here though because you don't know the failure statistics in advance. Kind of a multi-armed bandit problem of sorts.
- magicalhippo 4y ago
  Wouldn't the Arrhenius equation[1] be a good approximation? It's used in the industry[2] from what I know. Of course you'll need some data for calibrating the model, but if you got that? [1]: https://en.wikipedia.org/wiki/Arrhenius_equation https://en.wikipedia.org/wiki/Arrhenius_equation [2]: https://www.ti.com/lit/an/snva509a/snva509a.pdf https://www.ti.com/lit/an/snva509a/snva509a.pdf
  - buescher 4y ago
    Well, sometimes, and more frequently now at really small process nodes, but mostly no. Most electronic failures are basically mechanical and thermal cycling will cause fatigue failures more than elevated temperatures will accelerate things like electromigration. Lots of people still use 1960s style handbook methods anyway because there's no plug-and-chug replacement. The groundbreaking work here was by Michael Pecht back in the early nineties: https://apps.dtic.mil/sti/pdfs/ADA275029.pdf https://apps.dtic.mil/sti/pdfs/ADA275029.pdf
woleium 4y ago
Could also be more likely that it's cheaper to extend the life of an older DC by accepting higher temperatures and failure rates than to upgrade the hvac to accommodate newer higher density designs
- yjftsjthsd-h 4y ago
  Sounds like a win/win incentives alignment.
- synicalx 4y ago
  That creates a very unreliable DC though. I guess you'd factor the increase whole-of-facility downtime into your forecasts and work around that maybe.
- JJMcJ 4y ago
  The air conditioning is not free. Downtime isn't free. Depending on design, if the DC isn't very monolithic, then you can run with components failing and not causing much trouble, replacing when available, if your apps are designed to run on a zillion small CPUs, as I believe Google and Amazon are, instead of a giant monolithic computer, 1970s style. Could have heavier AC for critical components, the main routers and disk farms, for instance. Details of the calculations unknown to me.

by JJMcJ 4y ago

klysm 4y ago

Hard to do the math here though because you don't know the failure statistics in advance. Kind of a multi-armed bandit problem of sorts.

magicalhippo 4y ago
Wouldn't the Arrhenius equation[1] be a good approximation? It's used in the industry[2] from what I know. Of course you'll need some data for calibrating the model, but if you got that? [1]: https://en.wikipedia.org/wiki/Arrhenius_equation https://en.wikipedia.org/wiki/Arrhenius_equation [2]: https://www.ti.com/lit/an/snva509a/snva509a.pdf https://www.ti.com/lit/an/snva509a/snva509a.pdf
- buescher 4y ago
  Well, sometimes, and more frequently now at really small process nodes, but mostly no. Most electronic failures are basically mechanical and thermal cycling will cause fatigue failures more than elevated temperatures will accelerate things like electromigration. Lots of people still use 1960s style handbook methods anyway because there's no plug-and-chug replacement. The groundbreaking work here was by Michael Pecht back in the early nineties: https://apps.dtic.mil/sti/pdfs/ADA275029.pdf https://apps.dtic.mil/sti/pdfs/ADA275029.pdf

woleium 4y ago

Could also be more likely that it's cheaper to extend the life of an older DC by accepting higher temperatures and failure rates than to upgrade the hvac to accommodate newer higher density designs

yjftsjthsd-h 4y ago
Sounds like a win/win incentives alignment.
synicalx 4y ago
That creates a very unreliable DC though. I guess you'd factor the increase whole-of-facility downtime into your forecasts and work around that maybe.
JJMcJ 4y ago
The air conditioning is not free. Downtime isn't free. Depending on design, if the DC isn't very monolithic, then you can run with components failing and not causing much trouble, replacing when available, if your apps are designed to run on a zillion small CPUs, as I believe Google and Amazon are, instead of a giant monolithic computer, 1970s style. Could have heavier AC for critical components, the main routers and disk farms, for instance. Details of the calculations unknown to me.