a) Suppose that the mean time to failure of a single disk is 10,000 hours. Let us assume that the data is distributed among 100 disks. So one file is not on a single disk but is distributed across the 100 disks. What is the mean time to failure of some disk in an array of 100? What would be the result if one of the disk fails?

b) Now suppose that the same volume uses mirroring. What is the mean time to failure of some disk in an array of 100 and a repair time of 30 hours?

c) Why do the mean time to failure of each method vary so heavily? What benefits does mirroring have over not using it?