Abstract: A method, computer program product and computer system are provided. A processor receives a host input/output write operation, wherein the host input/output write operation includes host metadata regarding data represented by the host input/output write operation. The processor stores the host input/output write operation in one or more physical storage data units. A processor assigns a priority to the one or more physical storage data units. In response to receiving a host volume delete command associated with at least one of the one or more physical storage data units, a processor prioritizes data units of the host volume for deletion based, at least in part, on the assigned priority of the data units of the host volume, wherein data units with a lower priority are permanently deleted before data units with a higher priority.

Abstract: Embodiments of the present invention provide concepts for handling a handover of ownership of data from a source to a referrer in a data deduplication environment. By performing a handover of the ownership of the data from the source to the referrer, the number of processes required to access the data may be reduced and so the performance of the system may be improved. The identification of a source for performing the handover on may be performed by way of a volatile cache.

Abstract: A method, computer program product and computer system are are provided. A processor receives a host input/output write operation, wherein the host input/output write operation includes host metadata regarding data represented by the host input/output write operation. The processor stores the host input/output write operation in one or more physical storage data units. A processor assigns a priority to the one or more physical storage data units. In response to receiving a host volume delete command associated with at least one of the one or more physical storage data units, a processor prioritizes data units of the host volume for deletion based, at least in part, on the assigned priority of the data units of the host volume, wherein data units with a lower priority are permanently deleted before data units with a higher priority.

Abstract: Storing data volumes in virtual and physical address spaces such that the data units are contiguous in virtual address space but fragmented in physical address space. The mapping between virtual and physical address space is managed by a storage controller that is configured to implement deletes reversibly with a so-called soft delete, the soft delete being reversible up to a later permanent or hard delete. A soft delete triggers a compaction in which the data units of the to-be-deleted volume are gathered together in physical address space. During the time between compaction and hard delete (or restore), the soft deleted volume is thus stored in a space efficient manner. Moreover, the subsequent hard delete can be performed more quickly than if the soft deleted volume were still fragmented across physical address space freeing up space quicker.

Abstract: Storing data volumes in virtual and physical address spaces such that the data units are contiguous in virtual address space but fragmented in physical address space. The mapping between virtual and physical address space is managed by a storage controller that is configured to implement deletes reversibly with a so-called soft delete, the soft delete being reversible up to a later permanent or hard delete. A soft delete triggers a compaction in which the data units of the to-be-deleted volume are gathered together in physical address space. During the time between compaction and hard delete (or restore), the soft deleted volume is thus stored in a space efficient manner. Moreover, the subsequent hard delete can be performed more quickly than if the soft deleted volume were still fragmented across physical address space freeing up space quicker.

Abstract: A method and apparatus for relating a device name to a physical location of a device (202) on a network is provided. The network may be a serial loop network, for example a Fibre Channel Arbitrated Loop network. The network includes a plurality of devices (202) on or connected to the network (201) and a control device (205) with control over at least one of the devices (202). Each device (202) has a check output (204) independent of the network (201) with connection means (206) to a control device (205). The method includes the step of sending a device name from the check output (204) of a device (202) to the control device (205). The check output (204) of a device (202) is also connected to an external indication means for indicating the failure of the device (202).

Abstract: A method and apparatus for managing a loop network, the loop network (200) including at least one loop (206, 208), a plurality of devices (210) connected to the at least one loop (206, 208) via ports (211, 212), wherein at least two of the devices are initiators (207, 209). The method includes each initiator (207, 209) sending a frame to all other initiators (207, 209) in the loop network (200) identifying any ports (211, 212) which should not be used. Each initiator (207, 209) merges the information from all other initiators (207, 209) with its own information identifying any ports (211, 212) which should not be used resulting in all the initiators (207, 209) generating a single list of ports (211, 212) to be used which is consistent across all the initiators (207, 209). Each initiator (207, 209) applies an algorithm (300) to determine a common set of ports (211, 212) to be used by all the initiators (207, 209) and to balance port accesses across the loop network (200).

Abstract: An apparatus and method are disclosed for rebuilding a data storage array having plural communication paths. A first error detecting component detects an error at a data storage device of a data storage array. The data storage device has a plurality of ports and is operable to provide data for a preemptive rebuild. A port control component disables all but a single port of the data storage device. A preemptive rebuild component copies data from the data storage device to a spare data storage device using the single operational port. An alternative path maintenance component maintains an alternative communication path for use by other members of the data storage array and bypasses the data storage device. A second error detecting component detects an error at the data storage device during operation of the preemptive rebuild component. A device disabling component disables the data storage device after detecting a second error.

Abstract: A method is disclosed to locate a data storage device disposed in a data storage system. The method selects a target data storage device, identifies a target adapter port in communication with the target data storage device, and determines one or more target addresses, and determines one or more target World Wide Port Names (“WWPNs”). The method selects an enclosure, and a communication pathway disposed in that enclosure, and determines if any storage device ports interconnected with the communication pathway comprise a WWPN that matches any of said target WWPNs. If any storage device ports interconnected with the communication pathway comprise a WWPN that matches any of the target WWPNs, the method then identifies an adapter port in communication with that communication pathway, and determines if that any storage device ports in communication with the identified adapter port have claimed an address that matches a target address.

Abstract: A method and apparatus for recovery from faults in a loop network (500) is provided. The loop network (500) has a plurality of ports (520, 530, 532, 534) serially connected with means for bypassing the ports (520, 530, 532, 534) from the loop network (500). A control device (522, 524) is provided with bypass control over at least one of the ports (530, 532, 534). A host means (502) sends a command to the control device (522, 524) at regular intervals and the control device (522, 524) has a counter which restarts a time period at the receipt of each command. If the time period expires, the control device (522, 524) activates the means for bypassing all the ports (530, 532, 534) under its control. The loop network (500) may have two loops (516, 518) with at least some of the ports (520, 530, 532, 534) common to both loops (516, 518).

Abstract: Method, logic arrangement or program employ trunking identifiers to assign primary trunking connection between a switch pair.

Abstract: A method and apparatus for managing a loop network, the loop network (200) including at least one loop (206, 208), a plurality of devices (210) connected to the at least one loop (206, 208) via ports (211, 212), wherein at least two of the devices are initiators (207, 209). The method includes each initiator (207, 209) sending a frame to all other initiators (207, 209) in the loop network (200) identifying any ports (211, 212) which should not be used. Each initiator (207, 209) merges the information from all other initiators (207, 209) with its own information identifying any ports (211, 212) which should not be used resulting in all the initiators (207, 209) generating a single list of ports (211, 212) to be used which is consistent across all the initiators (207, 209). Each initiator (207, 209) applies an algorithm (300) to determine a common set of ports (211, 212) to be used by all the initiators (207, 209) and to balance port accesses across the loop network (200).

Abstract: A method and apparatus for improving performance of a loop network, in particular a Fiber Channel Arbitrated Loop. The loop network has two loops and a plurality of dual-ported devices each with one port on each loop. The method includes selectively bypassing redundant ports on the loops by a first command means in the form of a Fiber Channel Arbitrated Loop command to balance port accesses and to reduce the loop overhead by reducing the number of ports in each loop. In the event of a fault, bypassing the port of a device by a second command means in the form of a non Fiber Channel Arbitrated Loop command and enabling all the bypassed redundant ports with a single command to all ports using the first command means. The first command means does not enable the port bypassed by the second command means.

Abstract: A method and apparatus for managing a loop network, the loop network (200) including at least one loop (206, 208), a plurality of devices (210) connected to the at least one loop (206, 208) via ports (211, 212), wherein at least two of the devices are initiators (207, 209). The method includes each initiator (207, 209) sending a frame to all other initiators (207, 209) in the loop network (200) identifying any ports (211, 212) which should not be used. Each initiator (207, 209) merges the information from all other initiators (207, 209) with its own information identifying any ports (211, 212) which should not be used resulting in all the initiators (207, 209) generating a single list of ports (211, 212) to be used which is consistent across all the initiators (207, 209). Each initiator (207, 209) applies an algorithm (300) to determine a common set of ports (211, 212) to be used by all the initiators (207, 209) and to balance port accesses across the loop network (200).

Abstract: A method and apparatus for relating a device name to a physical location of a device (202) on a network is provided. The network may be a serial loop network, for example a Fibre Channel Arbitrated Loop network. The network includes a plurality of devices (202) on or connected to the network (201) and a control device (205) with control over at least one of the devices (202). Each device (202) has a check output (204) independent of the network (201) with connection means (206) to a control device (205). The method includes the step of sending a device name from the check output (204) of a device (202) to the control device (205). The check output (204) of a device (202) is also connected to an external indication means for indicating the failure of the device (202).

Abstract: A method and apparatus for relating a device name to a physical location of a device (202) on a network is provided. The network may be a serial loop network, for example a Fibre Channel Arbitrated Loop network. The network includes a plurality of devices (202) on or connected to the network (201) and a control device (205) with control over at least one of the devices (202). Each device (202) has a check output (204) independent of the network (201) with connection means (206) to a control device (205). The method includes the step of sending a device name from the check output (204) of a device (202) to the control device (205). The check output (204) of a device (202) is also connected to an external indication means for indicating the failure of the device (202).

Abstract: A method is disclosed to locate a data storage device disposed in a data storage system. The method selects a target data storage device, identifies a target adapter port in communication with the target data storage device, and determines one or more target addresses, and determines one or more target World Wide Port Names (“WWPNs”). The method selects an enclosure, and a communication pathway disposed in that enclosure, and determines if any storage device ports interconnected with the communication pathway comprise a WWPN that matches any of said target WWPNs. If any storage device ports interconnected with the communication pathway comprise a WWPN that matches any of the target WWPNs, the method then identifies an adapter port in communication with that communication pathway, and determines if that any storage device ports in communication with the identified adapter port have claimed an address that matches a target address.

Abstract: An apparatus and method are disclosed for rebuilding a data storage array having plural communication paths. A first error detecting component detects an error at a data storage device of a data storage array. The data storage device has a plurality of ports and is operable to provide data for a preemptive rebuild. A port control component disables all but a single port of the data storage device. A preemptive rebuild component copies data from the data storage device to a spare data storage device using the single operational port. An alternative path maintenance component maintains an alternative communication path for use by other members of the data storage array and bypasses the data storage device. A second error detecting component detects an error at the data storage device during operation of the preemptive rebuild component. A device disabling component disables the data storage device after detecting a second error.

Abstract: A method and apparatus for detection of a port name in a loop network is provided, particularly a loop network in the form of a Fibre Channel Arbitrated Loop (FC-AL). The loop network (100) has a plurality of devices (120) each device (120) having at least one port (211, 212) on the loop network (100). The method includes determining which ports (211, 212) are populated with devices (120) for which the unique port name (WWPN) is not known. The populated ports are then all bypassed and a mode is entered on the loop network (100) in which idle frames are transmitted around the loop network (100). One port is un-bypassed at a time and the port name from the un-bypassed port is received and recorded. The port name is received from the un-bypassed port in a Loop Initialisation Select Master (LISM) frame transmitted by the un-bypassed port.

Abstract: A method and apparatus for managing a loop network, the loop network (200) including at least one loop (206, 208), a plurality of devices (210) connected to the at least one loop (206, 208) via ports (211, 212), wherein at least two of the devices are initiators (207, 209). The method includes each initiator (207, 209) sending a frame to all other initiators (207, 209) in the loop network (200) identifying any ports (211, 212) which should not be used. Each initiator (207, 209) merges the information from all other initiators (207, 209) with its own information identifying any ports (211, 212) which should not be used resulting in all the initiators (207, 209) generating a single list of ports (211, 212) to be used which is consistent across all the initiators (207, 209). Each initiator (207, 209) applies an algorithm (300) to determine a common set of ports (211, 212) to be used by all the initiators (207, 209) and to balance port accesses across the loop network (200).