3 ms·
Let's say your high quality supply's yearly failure rate is 100 times less than the cheap ones The probability of at least a single failure is 1-(1-r)^70. Thi
by hn-throw 2y ago
Let's say your high quality supply's yearly failure rate is 100 times less than the cheap ones
The probability of at least a single failure is 1-(1-r)^70.
This is quite high even w/out considering the higher quality of the one supply.
The probability of all 70 going down is
r^70 which is absurdly low.
Let's say r = 0.05 or one failed supply every 20 in a year.
1-(1-r)^70 = 97%
r^70 < 1E-91
The high quality supply has r = 0.0005, in between no failure and all failing. If you code can handle node failure, very many, cheaper supplies appears to be more robust.
(Assuming uncorrelated events. YMMV)
- lillecarl 2y agoYeah but the failure rate of an analog piece of copper is pretty low, it'll keep being copper unless you do stupid things. You'll have multiple power supplies provide power on the same piece of copper
- hn-throw 2y agoTL/DR, isnt there a single, shared, DC supply that supplies said piece of copper? Presumably connected to mains? Or are the running on SOFCs?
- mycoliza 2y agoThe big piece of copper is fed by redundant rectifiers. Each power shelf has six independent rectifiers which are 5+1 redundant if the rack is fully loaded with compute sleds, or 3+3 redundant if the rack is half-populated. Customers who want more redundancy can also have a second power shelf with six more rectifiers.
- hn-throw 2y agoI'm going to assume this is on 3 phase power, but how is the ripple filtered?
- applied_heat 2y agoInductors and capacitors usually