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How to Run IOmeter for Disk I/O Testing

This document is meant to convey practical usage of IOmeter for purposes of testing disk IO of Windows servers.


You need to download the IOmeter software and several support files. Then, you can run IOmeter, dump out the results into a file, and parse them manually or via the listed web resources.

Downloading IOmeter

Download and extract the following software:

  • IOmeter
  • IOmeter Test File Generator
  • IOmeter Configuration File

NOTE: If you work here at Puryear IT, just go grab it from our downloads area.

Understanding the Results

Once the testing is complete, the easiest way to interpret results is to use this website:

I highly recommend familiarizing yourself with IOmeter’s GUI using the official documentation starting at Page 13

IOmeter may be run against the following:

  • Hard drives currently in use. In this case, a test file will need to be created on the root of the volume to be tested
  • Hard drives attached to the server, marked as online but not formatted and in use

Running IOmeter

  1. Create an IOmeter Test File:
    If directly testing a non-formatted drive, skip to step 2. This step is also optional as IOmeter can create its own test files, but it’s a bit flaky and takes a long time to generate the file

    1. Open a Command Prompt or Powershell window As Administrator
    2. From the prompt, run this command against the Test File Creator:
      C:> TestFileCreator.exe <FilePath>testfilecreator.exe 100G <drive letter>:iobw.tst
    3. NOTE: Make sure to delete this large file when done!
  2. Launch IOmeter and open the configuration file
    1. Run the extracted IOmeter.exe
    2. Click the Open icon
    3. Browse to iometer.icf and click Open
    4. The prebuilt test parameters run through 4k and 64k read/write spectrum, 30 minutes for each phase of the test.
  3. Select the drive to be tested in the Targets section
  4. Duplicate the number of workers by selecting the single worker and clicking the Duplicate button. Each worker represents a thread, create as many workers as you have processor cores.
  5. Once you have created all of the Duplicate workers, start the test by clicking the Green Flag start button.
  6. Choose the location IOmeter will save the results file and click save.
  7. You can monitor the results in real time by navigating to the Results Display tab and setting the Update Frequency to your desired interval, by default it will not update.
  8. To review the results, open and copy the contents of your test results file. Browse to http://vmktree.org/iometer/ and paste the contents into the results field. Click Submit. You want to paste the raw data from the CSV, not open the file in Excel and copy&paste that.

 Be sure to delete the test data file when done!

Learn how to read the results file.

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