5U84 storage shelf RAID controller
The Primary Storage Shelf contains two RAID controllers in I/O module slots. The controllers are labeled A and B, from left to right as you look at the rear panel of a shelf. Each controller has two sets of SAS-3 ports. From left to right the SAS-3 ports for each controller are labeled 3, 2, 1, and 0. The single SAS-3 port on the left side of each RAID controller connects to a SAS-3 port on the Expansion shelf.