HP Surestore Disk Array 12h - And FC60 Advanced User's Manual page 104

For high availability the hosts and disk arrays can be connected in any of the following
ways, with each connection of adapter and controller module creating a separate 2-node
Fibre Channel-AL:
•
One disk array with two controller modules with each controller module connected to
a separate adapter in a single host
•
In -Class and T-Class systems, two disk arrays with two controller modules per array,
K
connected to a single host with four Fibre Channel adapters.
The high availability version uses disk arrays having two (redundant) controller modules.
Each controller module is connected to a separate adapter. The two adapters can be
installed in one host or each adapter can be installed in a different host. Disk arrays having
redundant controller modules protect against single points of hardware failure by
providing an alternate hardware path to the host if an controller module, Fibre Channel
cable, host Fibre Channel I/O adapter, or internal Ultra2 SCSI bus fails. Applications can
continue to run after the failure of a single disk module. This is explained in the "Disk Array
High Availability Features" section in chapter 1.
Figure 35 shows the high availability version of the basic topology implemented on a host
system with two host Fibre Channel I/O adapters connected to a dual-controller module
disk array. One high availability version of the basic topology can be implemented in D-
Class servers.
Connecting multiple hosts to the Disk Array FC60 requires the use of Fibre
Note
Channel-AL hubs. Connecting the host through hubs preserves high-availability
in the event of a host adapter failure.
Topologies for HP-UX
104