Abstract: A RAID system employs a storage controller, a primary storage array having a plurality of primary storage units, and a spare storage pool having one or more spare storage units. A method of operating the storage controller in managing the primary storage array and the spare storage pool involves a testing by the storage controller of at least one repair service threshold representative of one or more operational conditions indicative of a necessity to repair at least one of the primary storage array and the spare storage unit, and a selective initiation by the storage controller of a repair service action for repairing one of the primary storage array and the spare storage unit based on the testing of the at least one repair service threshold.

Abstract: A system and method for changing the number of logical volumes in a drawer in a rack in a direct access storage device subsystem is disclosed. The method and system are able to change the number of logical volumes without disrupting access to the other logical volumes in the rack. Channel connection addresses, which are logical volume addresses as known by the CPUs, are freed by removing the old drawer and then are mused. If the new drawer has more logical volumes than the old drawer, the next unused channel connection addresses are used with the new drawer. In a subsystem having a storage controller for providing control for a plurality of direct access storage devices, the logical volumes are spread across multiple physical devices. The storage controller maintains configuration data for the entire subsystem in redundant, non-volatile storage locations reserved specifically for its use.