4 bay nas external interface 2x thunderbolt 2 memory capacity 8 tb number of installed hard drives 4 max hard drives 4 memory capacity per hard drive 2 tb internal interface sata raid levels 0 1 5 10 jbod 6 networking thunderbolt 2 connections 2x thunderbolt 2 case tower optical disc drives without hdd management hot swap server services photo album server itunes server network video monitoring upnp media server data backup apple time machine s