4 ms·
Statistics can do that. "If we were only X% durable, what are the odds we would have made it so far with no data loss?" Then pick a threshold p value you like
by tux3 3y ago
Statistics can do that. "If we were only X% durable, what are the odds we would have made it so far with no data loss?"
Then pick a threshold p value you like and that X% will be a reasonably confident estimate
If other words if you think you have 99.999999999 but you really have 99.9, Nature will correct you rather quickly. If reality persistently lets you get away with it, you can counterfactually deduce you must have more nines.
- vlovich123 3y agoYou’d have to randomly sample the set of all objects to do that. But I’m not aware of a database technique that lets you pick randomly. So I’m not sure how you’d validate the objects exist in practice. Checking 100 trillion objects seems expensive and time consuming. Doing it in flight while objects are being accessed is free but also heavily biased (ie those are files you’d be more likely to repair in the first place anyway)
- klysm 3y agoI don’t understand how to calculate those odds though. Like is it a continuous rate of event probability?
- tux3 3y agoThere's different sources of failures, and when you start claiming 11 nines of durability, you really have to go and think about all the different possible causes of failure. So it's not just a flat continuous rate, it's a sum of many different things. 11 nines is such a big number, you start modelling natural catastrophes, floods, solar flares, very unlikely discrete events as well.