Seven Point Six Milliseconds

A drive spins at 10,000 RPM, reports an average seek of 4.5 ms, and transfers at a sustained 160 MB/s. A database issues 16 KB reads at uniformly random offsets.

What is the average time for one read, and what effective rate does the drive deliver on this workload?

A

about 0.1 ms per read, about 160 MB/s

B

about 7.6 ms per read, about 2.1 MB/s

C

about 10.6 ms per read, about 1.5 MB/s

D

about 4.6 ms per read, about 3.4 MB/s