Windows Server disk striping & disk performance in Azure – IOPS

A little while ago I had problems with a virtual machine and the disk performance in particular. On this occaision, this was for an Azure VM, however the following can be used on any Windows server physical or virtual server / public cloud or private cloud. I called Microsoft Support who helped me navigate through the popular disk performance tool Iometer, below are the screenshots which can be used as an example. Take note of the settings of the screenshots, it’s handy to use as a guide and a kick start if you are not familiar with Iometer.

Disk Targets Tab


Access Specifications Tab


Results Display Tab. Notice the change of the update frequency from the default setting. Don’t forget to hit the Green flag at the top to kick it off.


Also too, while talking to Microsoft support, the person on the other end of the phone told me that these days they don’t use Iometer anymore and they normally use another commend line based tool called Diskspd Utility: A Robust Storage Testing Tool (superseding SQLIO) available from

Some examples of the Diskspd Utility tool are here:

This one will do Read / Write (64K):

 Diskspd.exe -b64K -d30 -h -L -o32 -t4 -r -w30 -c10240M S:\io.dat > resultR-W_64.txt

This one will do Read (64K):

 Diskspd.exe -b64K -d30 -h -L -o32 -t4 -r -w0 -c10240M S:\io.dat > resultread_64.txt

This one will do Write (64K):

 Diskspd.exe -b64K -d30 -h -L -o32 -t4 -r -w100 -c10240M S:\io.dat > resultwrite_64.txt

This one will do Read / Write (8K):

 Diskspd.exe -b8K -d30 -h -L -o64 -t4 -r -w50 -c10240M S:\io.dat > resultR-W_8.txt

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