Hello martinbuffleo,

With a Compellent system is a block level system. With data progression it will keep the blocks that are accessed the most on tier 1.  Data that is not being accessed a lot will be moved to tier2.  Here is a link to the Dell SC Series Storage and Microsoft Hyper-V. https://downloads.dell.com/solutions/storage-solution-resources/Dell%20SC%20Series%20Storage%20Best%20Practices%20for%20Microsoft%20Hyper-V%202016%20(CML1009V6o).pdf

Please let us know if you have any other questions.