Take a look at Windows Disk Management. Maybe the Disk needs to be assigned a drive letter.

@DustinB3403 said:

Reading the below stats is a bit, awkward to say the least it shows the information, but it's not entirely clear in my opinion. XenCenter seems to graph the disk usage more accurately at the Hypervisor level. (shown below is XO showing the Hypervisor level)

0_1452189348096_2016-01-07_12-55-36.png

When you select a VM though you get something similar to below.

0_1452189500086_2016-01-07_12-58-12.png

Now I personally, don't care so much about an individual VM's disk performance, I care about the host. So for me using XenCenter provides a "better" explanation of what I'm reading.

That's pretty cool. However keep in mind that in some cases, a single VM's disk performance can be hurting performance for the other VMs as well.