Mean Time Between Failures $($MTBF$),$ Mean Time To Replacement $($MTTR$),$ and

Mean Time To Failure $($MTTF$)$ are useful metrics for evaluating the reliability and

availability of a storage resource. Explore these concepts by answering the questions

about devices with the following metrics. Given that MTTF is three years and MTTR

is one day, answer the following questions

a$)$ Calculate the MTBF for each of the devices in the table.

b$)$ Calculate the availability for each of the devices in the table.

c$)$ What happens to availability as the MTTR approaches $0?$ Is this a realistic

situation?

d$)$ What happens to availability as the MTTR gets very high, i$.$e$.,$ a device that is

difficult to repair? Does this imply the device has low availability?