Secondary or augmented control of a storage array in a cost effective
manner is accomplished by connecting a host to the storage array via a
storage adapter independent of a RAID controller. The RAID controller
provides primary control for services standard to the RAID controller.
Augmented or enhanced services as well as backup control are provided by
a control module executing on the host, communicating to one or more
selected storage devices within the storage array via the storage
adapter. In one embodiment, the control module detects faults or failures
in the RAID controller, selectably directs storage commands to the RAID
controller, emulates a storage controller including a RAID controller,
and provides enhanced or augmented services such as conducting
diagnostic, firmware update, or disaster recovery operations.