The shadow migration source can only be set when a filesystem is created. In the BUI, this is available in the filesystem creation dialog. In the CLI, it is available as the shadow property. The property takes one of the following forms:
Local - file:///<path>
NFS - nfs://<host>/<path>
The BUI also allows the alternate form <host>:/<path> for NFS mounts, which matches the syntax used in UNIX systems. The BUI also sets the protocol portion of the setting (file:// or nfs://) via the use of a pull down menu. When creating a filesystem, the server will verify that the path exists and can be mounted.