I'm on a training course at the moment. In one of the labs I created a two-tier HDT pool from internal VSP disk. I tried to add in a third tier using AMS external storage however I couldn't see any available parity groups within the expand pool wizard. I tried adding the tier in with a High, Middle and Low external LDEV tier ranking however the result was still the same.
I also tried to create a new HDT pool using the AMS external disk but with no joy.
The instructor suggested that AMS is not supported for HDT, is this right?