The hard drives that Jason’s organization recently purchased have an MTBF of 300,000 hours. When can Jason expect the first drive to fail?

Mean time between failures (MTBF) is a measure of the reliability of a system. It is the expected amount of time that will elapse between system failures, but it is merely an average. Jason should expect that drives will fail, and that their average service life will be 300,000 hours. That means that half of the drives are likely to fail before 300,000 hours, and half will fail after that number.