When talking with your IO administrator about capacity, ask for both read and write capacity in either MB/s or IOPS. While the IO administrator may not classify the read and write requirements, because Oracle systems have very unique read and write characteristics, just to be safe, it is always best to ask for the requirements of both. Since we can gather IO requirements in both MB/s and IOPS, it really doesn't make much difference to us in which form capacity is delivered or expressed.

With both requirements and capacity defined and the data collection covered, let's use them together. The classic requirements-versus-capacity indicator is utilization. It can be applied in a wide variety of situations-from river water flow and factory production to Oracle performance analysis.

To calculate Oracle's CPU utilization, we need Oracle's CPU requirements (consumption) and the operating system's CPU capacity. Figure 9-3 provides the CPU requirements of 16,881.6 seconds of CPU and Figure 9-6 provides the capacity details of two CPU cores. Figure 9-2 provides the sample interval necessary to complete the CPU capacity calculation. We place these numbers into the utilization formula: