Hi Richardson,
I'm using version 07.35.53.00 which is the last batch of manufacture from 2011, by that time vSphere 4.1 had already came out and VAAI was already one of the function shipped with it.
Problem is I understand that many functions of the DS3400 were disabled from factory and must be enabled manually by executing some scripts from the System Storage Manager. writeCacheEnabled; readCacheEnabled; mirrorcacheenabled; mirrorEnabled are few of the examples.
I'm just thinking if I have missed a particular script to enable VAAI.
Thanks,
Grant