Abstract: A service processor has a memory, and a controller coupled to the memory. The controller is configured to perform part of a maintenance procedure on a data storage system such that a state of the data storage system transitions from a first state to a second state, and store, in a memory, a data structure identifying the second state. The controller is further configured to, after the maintenance procedure is aborted prior to completion of the maintenance procedure and after a transition of the state of the data storage system from the second state to a third state, (i) restore the data storage system to the second state based on the data structure stored in the memory, and (ii) complete the maintenance procedure.

Abstract: Load balancing of activities on physical disk storage devices is accomplished by monitoring reading and writing operations to blocks of contiguous storage locations on the physical disk storage devices. A list of exchangeable pairs of blocks is developed based on size and function. Statistics accumulated over an interval are then used to obtain access activity values for each block and each physical disk drive. A statistical analysis leads to a selection of one block pair. After testing to determine any adverse effect of making that change, the exchange is made to more evenly distribute the loading on individual physical disk storage devices.

Abstract: Load balancing of activities on physical disk storage devices is accomplished by monitoring reading and writing operations to blocks of contiguous storage locations, such as logical volumes on the physical disk storage devices to obtain disk utilization information. The disk utilization information provides a selection of one block pair. After testing to determine any adverse effect of making that change, an exchange is made to more evenly distribute the loading on individual physical disk storage devices. The exchange involves the use of a pair of specially configured logical volumes that receive copies of the data to be exchanged, allow a reconfiguration of the blocks in the block pair and the transfer of the data back to the other blocks in the block pair to effect the exchange.