I'm running into some difficulties getting pass-through disks to be accessible to a Hyper-v server 2003 r2 virtual machine.

Host OS : Server 2008 R2 full w/Hyper-V role

Guest OS : Server 2003 R2 (Windows Home Server)

The guest's OS disk is a pass-through disk on the IDE controller (not the best solution, but I can live with it). My storage disks will be pass-through disks on the SCSI controller. I'm able to see all of the disks that I'll be using for the VM on the host without issue.

The problem that I'm having is that I can't seem to get the guest OS to be able to 'see' the storage drives (as pass-through disks on the SCSI controller).

Here's what I'm doing :

  • On the host, the storage drive is set to 'Offline' just like the OS disk (this is required for pass-through to work).
  • In the VM, the storage drive is on the SCSI controller.
  • Hyper-V Integration Tools are installed in guest.

That's as far as I'm able to get. I don't see the drive in Computer Management, or in Windows Explorer (I've tried with an unformatted disk, as well as after formatting a partition). I am able to see a removable device that lists the disk's model number in the Guest, but I can't seem to access the storage. (I get an entry in Device Manager that needs drivers, but nothing on the Integration Tools disc works..)

Trouble-shooting steps I've tried :

  • If put the pass-through drive on the IDE controller, I can see it in the Guest.
  • If put the storage drive 'Online' in the host and create a VHD on it on the SCSI controller, I can see it in the Guest. I suppose I could create a fixed-size VHD that consumes the entire disk, but I'd rather not have that overhead.
  • I've also extracted the contents of the Integration Tools drivers (x86 and amd64) and tried pointing the disk controller to each of those, with no luck.

Can anyone offer suggestions as to how I can get this to work properly?


I suspect the disk is just offline in the guest. Did you go do Disk Manager in the VM and bring it on line?

I have to say, though, it's not worth bothering with. I'll bet that if you try to measure the performance overhead of putting fixed VHD on your disk and assigning that to the VM, you won't be able to tell the difference. And if you use the VHD, you can migrate the VM more easily. You can back it up. Etc.

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  • The disk isn't listed in Disk manager on the VM, all I see is the original OS disk. There's no prompt to initialize or anything like that (as happens with the two other ways that work mentioned above...) – Peter Bernier Feb 5 '11 at 4:18
  • mostly likely the problem is the disk is online on the host os! – tony roth Feb 6 '11 at 5:18
  • also why are you using pass thru quite sure you won't gain a thing by doing this. – tony roth Feb 6 '11 at 5:19
  • It says quite clearly in the question "On the host, the storage drive is set to 'Offline' just like the OS disk (this is required for pass-through to work)." I'd appreciate any other suggestions... – Peter Bernier Feb 8 '11 at 15:58
  • I meant "offline in the guest," as I've changed the text above to read. Is the VM SCSI driver installed? Do you see it in the VM? Perhaps you don't see your disk because the driver that exposes it isn't present. – Jake Oshins Feb 9 '11 at 7:31

Yes, it does support SCSI pass-through.

I tried some different disk configurations and it seems as though my inability to see the disk in the VM via the SCSI controller was related to the fact that it was in a USB3 enclosure (along with the host disk). This worked fine for IDE pass-through though, and both disks were always visible in the host, so I'm still not sure quite what the problem was.

I could have also done as Jake suggested and used a VHD occupying the entire disk, but I'm looking for a situation were I have direct access to the storage (ie, not through a VHD).

I'm responding simply so that if someone else winds up here via searching, it might help them along.

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