The specification of VAAI.

Hi

I want an information about the specification of  VAAI.

I am doing the test of VAAI like below.

Assign three Datastores(ds1,ds2,ds3) to the esx server, and repeat Storage Vmotion.

First I moved the data from ds1 to ds2.

After finish the first Storage Vmotion, then moved the same data to ds2 to ds3.

During Storage Vmotion, I was checking esxtop.

At the first Storage Vmotion, VAAI was worked.

But the secong Storage Vmotion, VAAI didn't work.

*I knew that If VAAI works, data copy works in background.

So I was also checking the status of Backend Director of VMAX.

If I did the second Storage Vmotion after the copy of the first Storage Vmotion is finished, VAAI worked well.

I want to know is this the specification of VAAI?

And If there is a document about this specification, I want to get  it.

Environment is like below.

OS : ESXi 5.1.0

Storage : VMAX SE

Thanks.

Yasuyuki