I would love to know what's the name of this connector so that I could stock some cables in aftermarket.
The Dell Parts for connecting the MB to the 4x Drives Backplane is called "GPPHP", yet the name doesn't suggest what's the port called. So apparently there is 4 SATA channel inside this port.
Note: The 4x drives backplane is a Mini-SAS HD (SFF-8613).