Fujitsu ETERNUS AX Series Installation And Cabling Manual page 36

Controller B and D port connection rules (for non HX2000 configurations)
• B and D ports are always the secondary paths to a stack.
• B and D ports always connect to the logical last disk shelf in a stack.
• B and D ports always connect to disk shelf IOM ports 3 and 4.
IOM port 4 is only used for quad-path HA and quad-path configurations.
• Controller 1 B and D ports always connect to IOM B (domain B).
• Controller 2 B and D ports always connect to IOM A (domain A).
• B and D ports are connected to the stacks by offsetting the order of the PCI slots by one so that the first
port on the first slot is cabled last.
The following illustration highlights how controller ports B and D connect in a multipath HA configuration
with one quad-port HBA and two stacks of disk shelves. Connections to stack 1 are shown in blue. Connections
to stack 2 are shown in orange.
| SAS cabling rules |
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