PowerEdge R720xd Supported Drives

Internal drive bay and hot-plug backplane:
Up to 26 x 2.5” HDD: SAS, SATA, Near-line SAS SSD: SAS, SATA
Up to 12 x 3.5” + 2 x 2.5" HDD: SAS, SATA, Near-line SAS SSD: SAS, SATA 

Datasheet: R720xd spec sheet