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Workload performance measurements

Performance Manager measures the performance of workloads on a cluster based on the high and low statistical values, which form the expected range of values for the workloads. It compares the actual workload statistical values to the expected range to determine when a workload is performing too high or too low. A workload that is not performing as expected triggers an incident to notify you.


Performance Manager workload performance measurements

In the illustration above, the actual value, in red, represents the actual performance statistics in the time frame. The actual value has crossed the performance threshold, which is the upper bounds of the expected range. The peak is the highest actual value in the time frame. The deviation measures the change between the expected values and the actual values, while the peak deviation indicates the highest change between the expected values and the actual values.

The following table lists the workload performance measurement values.
Measurement Description
Activity
  • For a policy group, the percentage of the QoS limit used by the workloads in the policy group.
    Note: If Performance Manager detects a change to a policy group, such as adding or removing a volume or changing the QoS limit, for example, the actual and expected values might exceed 100% of the set limit. If a value exceeds 100% of the set limit it is displayed as >100%. If a value is less than 1% of the set limit it is displayed as <1%.
  • For a cluster interconnect component, the percentage of time that workload operations are waiting at the interconnect.
Actual The measured performance value at a specific time for a given workload.
Delay For the network component, the percentage of the total response time for all user-defined workloads that are waiting at, or delayed by, the network component.
Deviation

The change between the expected values and the actual values. It is the ratio of the actual value minus the expected value to the upper value of the expected range minus the expected value.

Note: A negative deviation value indicates that workload performance is lower than expected, while a positive deviation value indicates that workload performance is higher than expected. If the expected values and the actual value are very low, in the hundredths or thousandths of a percent for example, the deviation will display N/A.
Expected The expected values are based on the analysis of historical performance data for a given workload. Performance Manager analyzes the highest and lowest statistical values for a workload over time to determine the expected values for a specific time. The values capture and display daily and weekly scheduled workload activity.
Expected Range The expected range of values is a forecast, or prediction, of what the upper and lower performance values are expected to be at a specific time. For the workload response time, the upper values form the performance threshold. When the actual value crosses the performance threshold, Performance Manager triggers an incident alert.
Peak The maximum value measured over a period of time.
Peak Deviation The maximum deviation value measured over a period of time.
Utilization For the network processing, data processing, and aggregate components, the percentage of busy time to complete workload operations over a period of time. For example, the percentage of time for the network processing or data processing components to process an I/O request or for an aggregate to fulfill a read or write request.