Specifications

2–4 Controller and Host Concepts
Unresponsive and Surviving Controllers
When a failover occurs in a dual-redundant pair of controllers, the controller that
ceases I/O processing is sometimes referred to as the unresponsive controller. The
controller that is failed over to is frequently called the surviving controller. The
surviving controller then has access to the unresponsive controller’s logical units, so
that it can continue to present them to the host, in addition to presenting host access to
its own logical units.
After failover has occurred, the host sends all commands through the surviving
controller. Once the unresponsive controller is fixed or replaced, the surviving
controller fails back control to the previously unresponsive controller.
See “Selecting a Failover Mode,” page 2–5 on the differences between failover modes
and how they work.
See “SET FAILOVER,” page 7–108 or “SET MULTIBUS_FAILOVER,” page 7–115
on how to reset the controller pair once the unresponsive controller has been fixed or
replaced.
See the HSG80 Array Controller ACS Version 8.3 and 8.4 Maintenance and Service
Guide on how to replace a controller.