Step1:check the IO type if it is a big pressure IO. If not, the IO will not save to disk, just hold in cache.
If customer wants to test out the maximum bandwidth available, it is recommended to use iometer tool, using a larger IO size, to test a larger area, in order to provide greater concurrent host business pressures.
For example, the order of 32K of IO, you can use 128 concurrent tests. and adjust the file size to 20GB.