In DPM you’ll have the ability to erase tapes by using the DPM console. Depending on your tape drive this will take a long time to erase. If you want to speed up this process you can enable short-erase by modifying the registry on the DPM server.
If your tape drive supports short erase, you can enable it on the DPM server by creating the DWORD UseShortErase under HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft Data Protection Manager\Agent.
Set the value of the DWORD to 00000000.
After this value is set, all erase operations on the DPM server will be short erases. To revert to long erases, remove this registry key.
Important: Though short erase is much faster than long erase, it does not completely erase the data from the tape. If you have a policy that all data from the tape must be erased and unrecoverable, do not enable short erase.