When executing a FlashArray upgrade from the FA-405 to a FA-X Series, into which slot...

When performing a specific legacy upgrade from a FlashArray FA-405 to a FlashArray//X Series , the 2-Port InfiniBand card must be installed in PCIe Slot 3 of the target controller (CT1).

Upgrade Architecture: The legacy FA-400 series utilized InfiniBand (IB) for its high-speed cluster interconnect. The modern FlashArray//X series utilizes PCIe/NTB over an internal midplane or different interconnects. However, during a non-disruptive upgrade (NDU) or data migration where the new //X controller is temporarily clustered with the old FA-405 controller to transfer state and data, they must share a compatible link.

Slot Reservation: The FlashArray//X hardware guide and upgrade procedures strictly designate Slot 3 (the top slot on the riser in many //X chassis configurations) as the reserved location for this temporary InfiniBand interconnect card. Installing it in Slot 0 or 2 would conflict with the primary Host I/O or backend connectivity paths, potentially causing the controller to fail the upgrade pre-checks or preventing the cluster from forming.