So I'd say ECC is not only important but insanely impactful. There's a reason why many organizations don't even want to hear about getting rigs with non-ECC memory.
I understand altitude has some kind of proportionality to cosmic ray exposure, and number of bits will multiply the probability of an error.. I'm presuming there is also an inherent error rate to DRAM separate from environment. But what are those numbers.
http://lambda-diode.com/opinion/ecc-memory#:~:text=A%20syste....
[edit]
Looks like the calculation was revised [0] after criticism:
> Under these assumptions, you'll have to wait about 33 to 600 days to get a 96% chance of getting a bit error.
What's more worrying is the variance, the above calculation is based on expected well behaved DRAM.. yet some computers just seem to have manufacturing defects that make the incidence of errors high enough to be a regular problem.
I'm too lazy to run the exact numbers right now, but with "4 GB, 96% percent chance, three days" as the hypothesis, I think you'll find that an experimental result of "8 GB, 0% chance, 14 days" is highly statistically significant.
Edit: rough back of napkin estimate - you're not seeing an event in roughly 10x trials (2x number of bits and ~5x number of days). Given hypothesis is true your experimental result has a probability of (1-0.96)^10 = very very small. Conclusion: hypothesis is false.
There's a lot of variables that go into RAM errors, including manufacturing quality and condition of the ram, the dimm, the dimm slot, the motherboard generally, the power supply, the wiring, and the temperature of all of those. Google was known for cost cutting in their servers, especially early on; so I wouldn't be surprised if some of that resulted in higher bitflip rate than running in commercially available servers. Things like running bare motherboards, supported only on the edges cause excess strain and can impact resistance and capacitance of traces on the board (and in extreme cases, break the traces).
No it doesn't. You're assuming an even distribution of errors, which is very much not the case.
Google found that the average number of errors is around that range, but they also found that only one third of their servers had any errors in a year.
"33 to 600 days to get a 96% chance of getting a bit error." Still, it seems way too high. I guess anyone with ECC RAM could confirm that they are getting those sort of recovered error rates?
My point is, when you say there is a "96% chance of having an error in THREE DAYS", one would EXPECT to be having issues like.. all the time? So I'm not disagreeing with you, but with the amount of non-ECC machines all over the world and how insanely stable modern machines are, it still seems like a very low risk.
Now of course I agree that if you want to take every precaution, go ECC, but simple observation prove that this "problem" can't be as bad as the numbers are saying.
Most will escape your attention.