What is meant with "2. Only basic disks are supported at this time."

Hello,

I was reading the HCL for BE 2012 for the Compatibility with PowerVault MD3220. There is a mark to "2. Only basic disks are supported at this time." what do they mean with it?! basic disks?!

I had an idea and thought about to configure a Linux Server with PowerVault MD3220 and a RALUS on which could be saved on a Media Windows Server with BE 2012 on it. Now I'm confused....what is supported and what not exactly..