CIFS is not the prefered destination. Performance is an issue with CIFS and especially trying to do things larger. You can't use more than 2 destinations per vDR. With a large disk to backup you should look to some other solution. vDR is not an appropriate solution for a disk this large.
Id add this tid bit to the discussion, for the setup i just referenced - I have the 1TB disks as VMDK's housed off a 2.99 OpenFiler iSCSI box (its simply used for backup reasons) ....
CIFS and Windows shares are the same thing. Windows shares are not the best for performance reasons and larger ones are less desirable than smaller ones. Long and short you can use two CIFS shares and you can make them 500GB each.
The current version of vDR seems to work well. There is an occational need to restart it but it works. runclear solution to use an iSCSI (or NFS) attached datastore is a far better destination. If you do need to use CIFS then that is what you use. You can also run multiple vDR appliances backing up a different set of VMs and at a different schedule.
