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)
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)