Sometimes when performance is important over other functionalities like snapshot fast clone which are provided by the VHD layer, we need to create raw VDI. 

Instructions

Note:
While this is not usually exposed and removes certain functionalities like snapshot and fast clone, it is always an option for data disks. RAW VDIs are known to perform better than VHD VDIs.

For the procedure to create a raw VDI, see the Citrix Hypervisor product documentation .