Top right, two of the 4 nodes, the other 2 nodes are underneath. This is a 2U rack mount unit. Bottom right the 1100W psu soon to be replaced by a 1400W supply.  All along the left hand edge are the HDD bays. This unit holds 12 x 3.5″ HDDs, 3 HDDs for each node. I have 4 x 1Tb Western Digital black drives (one for each node) in this unit.