Hi,
The only two solutions I see are:
A) You need another dedicated server for DPM and then move the SAS Dell PV-124T autoloader to that new machine.
B) You do away with the cluster and live with two standalone Hyper-V servers, then make the server with the PV-124T autoloader the DPM server.
Regards, Mike J. [MSFT] This posting is provided "AS IS" with no warranties, and confers no rights.