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.

MTTF ..........MTTR
3 Years .......1 Day

1. Calculate the MTBF for each of the devices in the table.

2. Calculate the availability for each of the devices in the table.

3. What happens to availability as the MTTR approaches 0? Is this a realistic situation?

4. What happens to availability as the MTTR gets very high, i.e., a device is difficult to repair? Does this imply the device has low availability?