HP Surestore Disk Array 12h and FC60 - Manual (Page 110)

110 Topologies for HP-UX
Single-System Distance Topology
Each instance of the single-system distance topology generally uses the following
hardware components:
• One host system or server
• Two Fibre Channel I/O adapters in each server
• One 10-port HP Fibre Channel-AL Hub
• One to four dual-controller module disk arrays (for high availability) or
One to eight single-controller module disk arrays (for non-high availability)
• Maximum 500 m fibre optic cable distance on each connection between the host and the
HP Fibre Channel-AL Hub and between the HP Fibre Channel-AL Hub and each disk
array, for a total Fibre Channel-AL cable length not to exceed 5000 m
One single-system distance topology can be implemented in each D-Class system, one or
two single-system topologies can be implemented in each
K
-Class system, and up to 11
instances of this topology can be implemented in each T-Class server. See your Hewlett-
Packard support representative for the number of adapters and topologies that can be
implemented in V-Class systems.
This topology uses one 10-port HP Fibre Channel-AL Hub. The two Fibre Channel I/O
adapters in the single host attach to two ports in the HP Fibre Channel-AL Hub, providing
redundant hardware paths between the host and the HP Fibre Channel-AL Hub. The
controller modules of dual or single-controller module disk arrays attach to some or all of
the remaining eight HP Fibre Channel-AL Hub ports. This topology creates a single Fibre
Channel-AL that resembles a star topology with the HP Fibre Channel-AL Hub acting as the
central switching element. The 10-port HP Fibre Channel-AL Hub is inserted between the
host and the disk arrays, increasing both the number of arrays (and total disk capacity) that
can be connected to a single host and the total length of the Fibre Channel cabling. The HP
Fibre Channel-AL Hub is a single point of failure in this topology.
Supported cable lengths for each segment of the Fibre Channel-AL include 2 m, 16 m, 50 m,
100 m, and 500 m. The maximum combined cable lengths for all segments, that is, the total
length of the Fibre Channel-AL should not exceed 5000 m because performance can
degrade due to propagation delay. Because of this it is recommended that the total cable
length of the Fibre Channel-AL be as short as possible. Fibre optic cables in lengths of 2 m,
16 m, 50 m, and 100 m cables can be ordered from Hewlett-Packard (see the Reference