Direct-SAN transport fails or configuration assistance is needed.
You must disable automount in diskpart on the proxy that the volumes are presented to, to ensure that VMFS volumes are not modified. (http://kb.vmware.com/kb/2002227)
Only VMFS type datastores are supported.
The volume for each datastore containing a VM that is intended to be backed up over Direct-SAN must be presented to the Backup Proxy.
The volume must appear in Disk Management within the Backup Proxy Server.
As the number of volumes presented to the Backup Proxy increases the delay for starting of the VM task may increase. This is due to the job scanning each volume. This can be mitigated by manually specifying in the Backup Proxy setting which datastores are connected.
Under certain circumstances volumes may not be automatically discovered and necessitate manually specifying which datastores are connected in the Backup Proxy settings.