ESXi (or any other OS in fact) will not see the data reduction savings, that's handled entirely by the storage.  It will report the data it has written to the datastore. On Unity, your LUN is thin provisioned, so just make the LUN bigger.  ESXi will see a larger datastore and write more data to it, but you will not be consuming any additional space on the backend since it's thin provisioned.  If you deploy the VSI plugin into vCenter, you will be able to report on the data reduction savings for the backend from vCenter.  That however will not change how much free space ESXi thinks it has on the datastore.
i'm using 350F solely for vmware vsphere 7 and the datastores are compressed now i'm unable to use the full potential of the compressed datastore that is, i'm running at 2:1 data reduction, my raw capacity is 2.5TB but i can only use 1.25TB of raw data since vsphere 7 sees the disk as begin 100% full... so what is the point of having compression if vsphere can't handle it? or what am i doing wrong? i don't see any setting in vsphere 7 that could solve this...
unity 350F with vmware compressed datastores