Statistics Engine Overview

For each workload test, whether it is running as a standalone test or as a part of a suite, statistics are being retrieved, stored, calculated, and presented in real-time.

This section gives an overview of the WorkloadWisdom statistics design that is running in the background to generate the charts and tables that you see in the Results Dashboard. You might notice a few seconds delay, as some statistics need to be calculated after they have been collected across all test ports.

Two tiers of statistics are processed: KPI statistics and non-KPI statistics. KPI statistics produce the Throughput, IOPS, Latency, and Command Mix Charts for the storage protocol layer (for example, SCSI for FC, and RPC for NFS). Non-KPI statistics are for the most part all statistics below the storage protocol layer (for example, TCP).

All statistics are processed and stored every 1 second. For Time charts, data points are plotted every 1 second by default in real-time. As more data points are plotted on the fixed-length chart in a long duration test, the data points are required to be aggregated to coarser intervals (called the aggregation level) to enable the complete data points set to fit on the chart. The aggregation levels are 15 seconds, 1 minute, and 5 minutes. WorkloadWisdom automatically determines the aggregation level required to show the highest fidelity of data possible.

If necessary, you can use the zoom function to see the data points at lower aggregation levels.

The data points are also provided in tabular form in snapshots of time. After the data points are plotted on the Time charts, they are calculated and displayed in the Summary Snapshot tables. The Summary Snapshots tables follow the currently displaying time range of the Time chart, which is from the start of test to the latest data point by default. If you zoom in to select a specific part of the Time chart, the Summary Snapshots table will recalculate.

For long duration tests (for example, multi-day tests), it can take several minutes for all the statistics to be calculated and displayed on the Results Dashboard, as the number of statistics to be processed can reach over a billion, and the size of the data points set can be over several GBs in size. During this time, you might see “N/A” for some statistics along with a clock icon. This indicates that calculation is still in progress.

In some extreme cases, calculation might time out or error out. This is indicated by orange colored text for the affected stats instead of the default black. If you encounter this, refresh the Results Dashboard one or more times.

WorkloadWisdom processes a massive amount of data points in real-time very efficiently. In some extreme cases, for example, multi-port multi-day tests, the number of data points to be processed requires additional time to calculate, summarize, and display.