Abstract: Method, system and computer program product are provided for detecting and correcting dropped writes in a storage system. Data and a checksum are written to a storage device, such as a RAID array. The state of the data is classified as being in a “new data, unconfirmed” state. The state of written data is periodically checked, such as with a timer. If the data is in the “new data, unconfirmed” state, it is checked for a dropped write. If a dropped write has occurred, the state of the data is changed to a “single dropped write confirmed” state and the dropped write error is preferably corrected. If no dropped write is detected, the state is changed to a “confirmed good” state. If the data was updated through a read-modified-write prior to being checked for a dropped write event, its state is changed to an “unquantifiable” state.

Abstract: A method of providing a power failure warning in a storage system includes partitioning early power off warning (EPOW) control logic of a storage enclosure to be symmetric with a power distribution network power domain. A power failure warning system for a storage system having a plurality of storage enclosures includes a power system control module coupled to a power supply for control and management of input power to the storage system. An output stage of the power supply is dedicated to a first virtual storage enclosure within one of the plurality of storage enclosures.

Abstract: A high density storage enclosure houses first and second pluralities of hard disk drives (HDDs). The enclosure may be partitioned into a plurality of virtual enclosures, the first plurality of HDDs being associated with a first virtual enclosure and the second plurality of HDDs being associated with a second virtual enclosure. In the event of a failure within one of the virtual enclosures, an SES in the failed virtual enclosure is isolated from the rest of the virtual enclosure. Then, an inter-enclosure link may be enabled between the failed virtual enclosure and another virtual enclosure. The isolated SES processor may then be accessed to obtain data associated with the failure and to execute commands associated with a recovery process.

Abstract: A storage system includes a RAID adapter, disk array switches, sub-processors, and hard disk drives. A disk-related operation is initiated in the RAID adapter which dispatches a command to a disk array processor (or sub-processor) in an enclosure for the processor to perform the operation on one or more drives. The adapter may dispatch the command to a processor in a single enclosure through a disk array switch or to processors in multiple enclosures through switches in upstream enclosures. The adapter is then free to perform other functions. The processor commences the specified operation on one or more selected drives. Upon completion of the operation, the results are transmitted by the processor and received by the adapter. Offloading the task to the distributed sub-processors reduces the burden on the RAID adapter, reduces system bandwidth usage, and enables access to other drives to be maintained.

Abstract: A high density storage enclosure houses first and second pluralities of hard disk drives (HDDs). The enclosure may be partitioned into a plurality of virtual enclosures, the first plurality of HDDs being associated with a first virtual enclosure and the second plurality of HDDs being associated with a second virtual enclosure. Configuration of the storage enclosure is performed by an SES processor in the storage enclosure accessing configuration parameters received from an external configuration unit coupled to the storage enclosure. The virtual enclosures may be configured as two (or more) independent virtual enclosures on two (or more) independent fabrics or may be configured in a trunked manner. Power supplies and cooling blowers in the storage enclosure may also be partitioned and assigned to be managed by SES processors in the virtual enclosures.

Abstract: A method to assign addresses to a plurality of data storage devices, by providing a switch and (N) data storage devices, where each of those (N) data storage devices is interconnected with said switch. The method further establishes (M) arbitrated loop physical addresses (“AL_PAs”), where (M) is less than (N), and assigns a different one of each of the (M) AL_PAs to a different one of the (N) data storage devices, such that the (N) data storage devices comprise (M) AL_PA-assigned data storage devices and (P) non-address-assigned data storage devices. The method then detects a failure of an (i)th AL_PA-assigned data storage device, and transfers the (i)th AL_PA from the failed address-assigned data storage device to a (j)th data storage device, where that (j)th data storage device comprises one of the (P) previously non-addressed data storage devices.

Abstract: The advanced management module services in a data processing system are configured to determine the system load and provide an input to the early power off warning detection logic that evaluates the power system state to detect a condition when power resources are insufficient to maintain the write caching storage system power within defined acceptable limits. The early power off warning detection logic generates a notification based on the system load and the available power supply resources to maintain maximum availability and reliability characteristics.

Abstract: A mechanism is provided for autonomic component service state management for a multiple function component. The mechanism determines whether independent functions within a multiple function service boundary can be serviced. When a single function experiences a failure that requires service, repair, or replacement, the surviving functions notify the service management software of the state of the independent functions. The service management software then determines the state of the overall component and implements the appropriate service method.

Abstract: A data storage library includes a drive enclosure bay which can be adapted to work with multiple air-flow configuration requirements. This is accomplished by creating air-flow ports in the top and bottom of the drive enclosure bay, by forming drive tray slots and printed circuit board ports in associated drive trays, by creating frame ports and PCB notches in associated interface cards, and replacing traditional connectors with slimmer but longer connectors that provide additional standoff and improved air-flow.

Abstract: A mechanism for in situ verification of capacitive power support is provided. A memory system uses a super capacitor to support a voltage rail when input power is lost or interrupted. The voltage discharge curve is a function of load and capacitance of the component. By stepping the regulated power supply to a lower output within the voltage range and recording voltage and current draw at the super capacitor as it discharges to the new regulator output voltage, the super capacitor holdup capability can be tested.

Abstract: A computer-implemented method replaces a redundant array of independent disks (RAID) array member storage device configured in high density packaging. The high density packaging includes a plurality of field-replaceable units (FRUs). Each FRU has an associated plurality of storage devices. A first spare storage device of a first FRU is captured. The first FRU is dedicated as a plurality of spare storage devices by a RAID controller. A small computer system interface (SCSI) enclosure services (SES) processor (SESP) is initialized to read data from the RAID array member storage device and transfer the data to the first spare storage device. The first spare storage device and the RAID array member storage device are co-resident within a serial attached small computer system interface (SAS) expander local port domain.

Abstract: A method of destage management of redundant data copies in a cache storage subsystem includes providing a plurality of target storage devices, each of the plurality of target storage devices capable of storing a complete copy of a data image. The data image and the plurality of target storage devices are subdivided into a plurality of sub-regions, each of the plurality of sub-regions organized such that a minimum cumulative total of the plurality of sub-regions on the target storage devices equals a number of sub-regions required to form the complete copy of the data image. Data is destaged from a write cache to the plurality of sub-regions on the target storage devices in an order such that a minimum number of sub-regions can be combined to restore the complete copy of the data image.

Abstract: A method to supply power to one or more battery-backup assemblies, wherein the method supplies a first controller, a second controller, a first battery-backup assembly, and a second battery-backup assembly. The method further supplies a power bus interconnected to the first controller, the second controller, the first battery-backup assembly, and the second battery-backup assembly, and a first power supply and a second power supply interconnected with the power bus. The method provides power to the first controller and to the second controller and to the first battery-backup assembly over a first period of time, and provides power to the first controller and to the second controller and to the second battery-backup assembly over a second period of time, where the first period of time differs from the second period of time.

Abstract: A configuration of an array of storage devices compliant with a fiber-channel arbitrated loop (FC-AL) specification includes first and second controllers having integrated first and second SCSI enclosure services (SES) processing devices acting as leader processors. Third and fourth controllers are coupled to the first and second controllers and act as subordinate processors. The third and fourth controllers have integrated third and fourth SCSI enclosure services (SES) processing devices. Each of the SES processing devices synchronizes and merges data to create a single control image for the entire configuration, presenting a single SES instance to a storage device interconnect network and to host controller software.

Abstract: A method is disclosed to install a component in an information storage and retrieval system. The method provides an information storage and retrieval system comprising a system processor and system data, and a component comprising persistent component data. The method attaches the component to the information storage and retrieval system while the information storage and retrieval system remains in normal operation, and determines, while the information storage and retrieval system remains in normal operation, if the component is compatible with the information storage and retrieval system. If the component is compatible with the information storage and retrieval system, the method then places the component into service while the information storage and retrieval system remains in normal operation.

Abstract: To ensure integrity of non-volatile flash, the controller programs the non-volatile memories with background test patterns and verifies the non-volatile memories during power on self test (POST) operation. In conjunction with verifying the non-volatile memories, the controller may routinely run diagnostics and report status to the storage controller. As part of the storage controller power up routines, the storage controller issues a POST command to the controller via an I2C register that is monitored by the storage controller. The storage controller may determine that the non-volatile flash is functional without any defects, and the controller may remove power from the non-volatile flash to extend its reliability. Periodically, in the background, the controller may run diagnostic routines to detect any failures associated with the volatile memory and the controller itself.

Abstract: A memory system has mechanisms for scavenging capacity of a super capacitor by removing, or reducing, system load from the super capacitor when the super capacitor voltage decays below a low threshold. The mechanisms then restore the system load to the super capacitor when the super capacitor voltage ramps back above a high threshold. A controller may reduce system load by placing a volatile memory system in a standby state and disabling a field effect transistor to remove power from a non-volatile memory system. A controller may adjust the high threshold and/or a low threshold by setting a digitally controlled potentiometer in a threshold detect circuit via an I2C bus.

Abstract: Systems and methods for allocating task control blocks in an information storage and retrieval system are disclosed. Task control blocks for new writes and reads are allocated by the cache code after a determination of the number of task control blocks already allocated for other tasks.

Abstract: Data storage systems and methods and computer program product for managing data storage systems are provided. The system includes at least first and second storage enclosures, each having a plurality of hard disks configured as first and second arrays of disks and an intra-enclosure path between the first and second arrays. The intra-enclosure path is disabled during normal operation of the storage system. Inter-enclosure paths respectively link the first arrays in the first and second storage enclosures and the second arrays in the first and second storage enclosures and are enabled during normal operation of the storage system.

Abstract: A method, system and computer-usable medium are disclosed for providing management of serial attached small computer system interface (SAS) storage devices. A host computer comprises a storage controller connected to a SAS port expander comprising a plurality of ports that are logically assigned to target storage devices. The device ports of all storage devices physically attached to the SAS port expander are bypassed to remove their logical SAS expander port assignments. The storage controller unbypasses the device ports, allowing it to recognize the presence of all physically attached storage devices. The recognized storage devices are inventoried and storage devices that are not logically assigned a SAS expander port are designated as being spare storage devices. SAS expander ports are logically assigned to the non-spare storage devices and SAS storage operations are performed.