PowerEdge R415 Supported Drives

Internal drive bay and hot-plug backplane:
Up to 4 x 2.5” HDD: SAS, SATA, Near-line SAS SSD: SAS, SATA
Up to 4 x 3.5” HDD: SAS, SATA, Near-line SAS SSD: SAS, SATA

Server also supports cabled chassis configuration 

Datasheet: R415 spec sheet