HP StorageWorks HSG80 ACS Solution Software V8.8 for IBM AIX Installation and Configuration Guide (AA-RV1HA-TE, March 2005)

Planning a Subsystem
32 HSG80 ACS Solution Software V8.8 for IBM AIX Installation and Configuration Guide
At any time, host port 1 is active on only one controller, and host port 2 is active
on only one controller. The other ports are in standby mode. In normal operation,
both host port 1 on controller A and host port 2 on controller B are active. A
representative configuration is shown in Figure 8. The active and standby ports
share port identity, enabling the standby port to take over for the active one. If one
controller fails, its companion controller (known as the surviving controller) takes
control by making both its host ports active, as shown in Figure 9.
Units are divided between the host ports:
■ Units 0–99 are on host port 1 of both controllers (but accessible only through
the active port).
■ Units 100–199 are on host port 2 of both controllers (but accessible only
through the active port).
Transparent failover only compensates for a controller failure, and not for failures
of either the Fibre Channel link or host Fibre Channel adapters.