Which of the following would cause a bottle neck, if the value is more than 2? (Choose all that apply)

A.
Disk Transfers/sec

B.
Current Disk Queue Length

C.
Average Disk Queue Length

D.
Disk Bytes/sec

Explanation:
When these disk counters is more than 2, it will cause a bottle neck.
Incorrect Answers
A: If this value is consistently over 80 for a single physical disk drive, and the average disk/sec transfer is less than acceptable, this disk drive is slowing down the overall system performance.
D: This measurement is the rate at which bytes are transferred to or from the disk during write or read operations. Add up this counter’s values for each disk drive attached to the same SCSI channel, and compare it to the throughput of the SCSI bus. If this summed value is close to 80% of the throughput for the SCSI bus, the SCSI bus itself is becoming a bottleneck.
References:

Charles J. Brooks, Server+ Certification Exam Cram 2 (Exam SK0-002), QUE Publishing, Indianapolis, 2006, p. 347