Which of these factors indicates a high likelihood that the performance of a virtual machine is
being constrained by disk I/O?

A.
A large number of kilobytes read and written

B.
A high device latency value

C.
A large number of bus resets

D.
A large number of commands issued

Explanation:
Disk performance bottlenecks are usually due to either Disk queue lenght or Disk Latency. Refer internet search.