An Implementation Engineer is installing the first DirectFlash Shelf (DFS) on a FlashArray//XR4 controller.

The FlashArray//XR4 utilizes onboard 100GbE RoCE (RDMA over Converged Ethernet) ports for connecting to the first loop of DirectFlash Shelves, removing the need for dedicated PCIe add-in cards for the base configuration. The port mapping for these onboard backend ports differs from previous generations.

On the //XR4 controller chassis, the specific Ethernet interfaces designated for the first DirectFlash Shelf loop are typically the high-numbered onboard ports. In this specific exam context and hardware revision, ETH 18 and ETH 19 are identified as the correct primary backend connectivity ports .

Implementation Engineers must connect the QSFP28 cables from the "uplink" ports on the first shelf (IOM0 and IOM1) to ETH18 and ETH19 on the controllers (CT0 and CT1) respectively. Using incorrect ports (like ETH0/1, which are management) would result in the shelf not being detected by the storage fabric.

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