In the previous article, we covered the storage options for Hyper-V and described the many choices between directly attached or SAN storage, fibre channel or iSCSI, passthrough or VHD, Virtual SCSI or Virtual IDE, etc. This post discusses the option to store your VHD files in a CIFS/SMB file server share. This works fine with Hyper-V, although everyone is quick to remind me that this would be slower than block storage, if all else is the same. However, with faster IP networks (including 10Gb Ethernet) and the improvements in the SMB v2 protocol, you might be tempted by the added flexibility in your storage management.
How to do it? Storing your Hyper-V files on a file server is pretty straightforward. There are, however, a few of things that you need to implement this properly with Hyper-V.
First of all, remember to grant access to the computer account of the computer running Hyper-V. This is the DOMAIN\COMPUTERNAME$ account, which you can use in the same way you would use a regular user account when granting permissions.
The second thing is that you need to do is use a UNC path when pointing to the file server. This is a path that looks like \\SERVERNAME\SHARENAME. Using a mapped drive or mount point does not work with the Hyper-V Manager tool.
Last but not least, you need to do this at the computer running Hyper-V (or connected via Remote Desktop to that computer).
If you try to use the Hyper-V Manager tool remotely, you will get error messages saying your “access was denied”.
You can work around this by using constrained delegation to allow a workstation to work on behalf of the computer running Hyper-V.