Basic question - what kind of data do these RDMs actually keep?
If we are talking here about some apps covered by NetApp SnapManager products (say Exchange), then you can use SnapManager to migrate the data.
If not (or you don't have / use SnapManager), then utilising exisiting backup software & agents to do a 'traditional' backup & restore seems like a feasible way. To make the whole excercise quicker, you can create a share on the NetApp filer & use it as backup staging area (instead of messing with tapes).
>Basic question - what kind of data do these RDMs actually keep?
The RDM is connected to a virtualized file server and contains windows shares and data.
Of course we do migrate cifs-data directly to the netapp, but this VM is in another domain and we do not have multistore in place. So we have to wait until we can get rid of this multi-domain-structure...