There are two distinct fabrics, each composed of one (only!) QLogic SANbox 5800 switch.
Each switch has 20 2/4/8-Gb/s fibre channel ports to which clients (servers and disc arrays) are connected, and 4 10-Gb/s XPAK switch interlink ports. None of the interlinks are currently used.
For optimal multipath redundancy, each client server and disc array should be connected to both fabrics.
Machines marked with a '' are currently fitted with a single fibre port only; they cannot be set up for multipathing.
neilb: "Where I've added a port ie p[012], the number is as indicated on the hardware. Note that some hardware is indexed from 0 and others from 1, eg the Dell servers label them port 1 and port 2, but the Evo's and Nexsan boxes label them host 0 and host1."
'NC' means that the named machine has been cabled to the switch port, but the cable is not currently connected at the machine end. This should only happen if/when a machine has been physically removed for maintenance of some kind.