Attaching an existing VHD that is not in SCVMM libraries

[guest]

When you create an additional disk drive to a VM, you can attach to this drive an existing VHD from the SCVMM library or create on-the-fly a new VHD and attach it. The cmdlet Add-VirtualDiskDrive allows you to have one of the two combinations. I want to know whether you can simply attach an existing virtual hard disk that is not stored in SCVMM libraries.

In our production environment, we have application VMs that requires a separate VHD. Those VHDs already contain application-specific data. Storing such VHDs in libraries is not practical ( ~100 VHDs distributed on different Hyper-V hosts) and is not recommended by our security folks (no share of private data). And I don't want to create new VHDs on the fly and re-populate it with existing data before attaching it to a VM.

Appreciate any thought/suggestion you may have for this problem,

[guest]

These VHDs are already in circulation so I am not understanding why they are any more secure if they are not in the library. Also I think it is safe to say that once these VHDs are with a specific VM that they will stay with the VM. That said, once configured they will move with the VM as needed, in other words this is not a long term issue you just need a one time solution...

OK so basically you have a few choices...

1) Use Hyper-V Manager to attach the pre-existing vhd to the VM, make sure you move it into the VM folder since you are using SCVMM.
2) Copy the vhd into the library and use SCVMM to attach it (If this is a one-time thing then the vhd could be deleted after the fact).