If you have configured read cache then this is related to read performance only. If you try to write in this array then you may not see any significant improvement.
So it depends upon what and how you are testing performance for this array.
You can install IO meter which will virtually create load on the array for testing purpose.
You can get many videos to learn the use of IO meter.
http://www.iometer.org/doc/downloads.html
You can refer below link to get some idea as well,
https://administrator.de/forum/performance-messung-iometer-storage-348765.html
Hope this helps!
Regards
Subhajit
I am an HPE employee
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