Monitoring Microsecond Storage – Perfmon with a little help from Powershell

I do a lot of performance analysis. I use perfmon as part of my toolkit it is great for performance data collection. I can use it to watch live performance data or I can save performance data for later analysis.

One limitation I have come across with perfmon is that the tool will only display performance data for disk latency (LogicalDisk(*)\Avg. Disk sec/Reads)  in milliseconds.

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I can take a saved perfmon file and export the data to a csv file or a database and then view the data in at a more granular level.

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Opening the csv file in Excel can now see the analyse the disk latency in microseconds.

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This still leaves me with the limitation of not been able to view microsecond latency data in the toolkit. This is especially limiting when I want to view live performance data, enter powershell.

Powershell has a cmdlet called get-counter which will display live performance data and for disk latency this is displayed in microsecond granularity  . I can simply type something like the following example:

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Live performance data for disk latency will be returned to the screen.

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Summary

Perfmon is a great tool for collecting performance data. One limitation I have come across is that although disk latency is recorded at sub-millisecond level it is only displayed on the tool rounded to the nearest millisecond . Powershell offers the ability to display live disk latency at sub-millisecond latency this could be easily scripted to average latency over a time period or create a graph of live performance data something we will explore in  a later post.

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