Question

Availability is the most important consideration for designing servers, followed closely by scalability and throughput. a. [10]<1.7>Wehaveasingleprocessorwithafailureintime(FIT)of100.What is the mean time to failure (MTTF) for this system

Answer 1

a) Mean Time to failure (MTTF) = (10^7) hours

b) Availability of the system = 1

c) Mean Time to failure for 1000 processors = 10^4 hours.

Explanation:

a) Failures in time (FIT) is traditionally reported as failure Per billion hours Of Operation.

1 billion = (10^9)

FIT = 100/(10^9) = 10^-7

MTTF = 1/FIT = 1/(10^-7) = (10^7) hours

b) Availability of the system = MTTF/(MTTF + MTTR)

MTTR = mean time to repair = 24hours

Availability of the system = (10^7)/((10^7) + 24) = 0.9999 = 1

c) FIT = 1000 (processors) × 100 (FIT per processor) = (10^5) per billion hours of operations = (10^5)/(10^9) = 10^-4

MTTF = 1/FIT = 1/(10^-4) = (10^4) hours

QED!!