Hyper-V Disk Copy

Question

I have one VM and this VM have 2 disks, let say disk-1 located in D drive on hyper-v host and disk-2 located in E drive on hyper-v host.

When i copy file inside the VM from disk-1 to disk-2, why the copy is flow via network and not directly across the disks on hyper-v host?

Answer 1

Hello Handian,

As far as I know, when you copy files between disk-1 and disk-2 inside the VM, even though both virtual hard disks (VHDs) reside on the same Hyper-V host (D: and E: drives), the copy operation is handled entirely within the guest OS. The VM treats each VHD as a separate virtual device, and it has no awareness of their physical location on the host. As a result, the data flows through the VM’s virtual storage stack and memory, not directly between host drives.

If you’re seeing network-like traffic during the copy, it may be due to how the VM is configured, especially if the disks are attached via virtual SCSI or if integration services are influencing I/O paths. This isn’t actual network traffic, but rather internal I/O that can resemble it in performance monitors.

To optimize performance, consider placing both VHDs on the same physical disk or using pass-through disks if direct host-level access is required.

If this explanation helps clarify the behavior, please hit “Accept Answer” so others can benefit too 😊.

Jason.