I have a guest server (Win08 R2) on an ESX 5.1 host with a few raw mapped drives back to my Dell/Compellent SAN. When I extended the volume on the SAN (500GB ro 750GB) it works fine. I now need to extend it to 1TB. The SAN (and support) sees the volume as 1TB. I rescanned the drives multiple times and tried this scenario on a second volume on the same server. Windows 2008 R2 doesn't see the unallocated space. The host see the drives as basic.
I also tried the same scenario on a Windows 2012 R2 Server and Windows 2003 Server. They both were successful.