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lisivka | 9 years ago

I have no idea, why you downvoted. Stability test is important step of cluster building. If probability of something broken in new server is 10% then probability of something broken in new cluster of 10 servers is 1-(1-0.1)^10 = 65% .

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masklinn|9 years ago

Because they objection has nothing to do with the original comment. Bitflips are not a RAM stability issue.

lightedman|9 years ago

"Bitflips are not a RAM stability issue."

Cosmic radiation bitflips are BS. No cosmic rays reach ground level. The chance of a, say, Al-28 nucleus successfully penetrating the entire atmosphere is as close to zero as it could be possible to get. Basic physics. Something with such a high charge density won't penetrate ~100km of atmosphere and magnetic field. Even a basic muon wouldn't get through a sheet of aluminum foil and those are still capable of actually getting (barely) through the atmosphere.

The chances of cosmic radiation causing a bitflip are pretty much in the range of "Elvis coming into town on Nessie." Radiation originating from inside the system itself is much more likely a cause.

lisivka|9 years ago

Bitflips are not a RAM stability issue, they happen randomly due to radiation, but radiation is not random, especially in my area (I live not far from Chornobyl).