Abstract: A storage system and method for identifying a faulty link the storage system is disclosed. The storage system includes a plurality of target devices and at least one expander configured to communicatively couple a plurality of initiators to the plurality of target devices. Each initiator of the plurality of initiators monitors occurrences of link disruptions independently, wherein upon detecting occurrences of a predetermined number of link disruptions within a predetermined time period, a reporting initiator reports a detection of a faulty link in the multi-initiator topology and requests an arbitrator to identify at least one peer initiator in the multi-initiator topology that shares at least one shared link with the reporting initiator. This reporting initiator and its peer initiators then jointly execute a common diagnostic process to identify the faulty link in the multi-initiator topology.

Abstract: A storage system and method for identifying a faulty link the storage system is disclosed. The storage system includes a plurality of target devices and at least one expander configured to communicatively couple a plurality of initiators to the plurality of target devices. Each initiator of the plurality of initiators monitors occurrences of link disruptions independently, wherein upon detecting occurrences of a predetermined number of link disruptions within a predetermined time period, a reporting initiator reports a detection of a faulty link in the multi-initiator topology and requests an arbitrator to identify at least one peer initiator in the multi-initiator topology that shares at least one shared link with the reporting initiator. This reporting initiator and its peer initiators then jointly execute a common diagnostic process to identify the faulty link in the multi-initiator topology.

Abstract: A system and method for providing Quality of Service (QoS)-based data services in a direct attached storage system including at least one physical drive comprises logically dividing the drive or drives into a plurality of pools implemented according to CRUSH algorithms or other declustered RAID configurations. The plurality of pools are then managed as declustered RAID virtual drives. The system and method further comprises identifying a pool with a performance characteristic and monitoring the pool to detect “hot” data within the pool, which may then be migrated to a pool with a more desirable performance characteristic. The system and method further comprises prioritizing critical operations performed on a pool based on the performance characteristic of the pool.

Abstract: A storage system and method for preventing propagation of link reset among initiators in the storage system is disclosed. The method includes issuing a link reset command by the initiator, and entering the initiator into a back-off period immediately following the issuing of the link reset command. The initiator remains idle for the entire duration of the back-off period and resumes its operations at the end of the back-off period.

Abstract: The present disclosure is a system and method for improved RAID rebuilds under host IO conditions, that greatly improves rebuild times and prevents host IO starvation. A queue in a drive that is part of the RAID is used to store rebuild and host IO requests, with rebuild IOs issued to the head of the drive queue. Rebuild requests in the drive are delayed by a delay time. This delay ensures there is no unintended side effect of this invention that may result in host IO starvation for the RAID system. Delay is computed as a heuristic function from a plurality of variables, such as disk head response times, time allotted for rebuild, number of rebuild threads, drive behavior, rebuild IO profile, host IO profile including workload and locality, and a timeline of sequenced events, which in one preferred embodiment cycles every 70 seconds.

Abstract: The present disclosure is a system and method for improved RAID rebuilds under host IO conditions, that greatly improves rebuild times and prevents host IO starvation. A queue in a drive that is part of the RAID is used to store rebuild and host IO requests, with rebuild IOs issued to the head of the drive queue. Rebuild requests in the drive are delayed by a delay time. This delay ensures there is no unintended side effect of this invention that may result in host IO starvation for the RAID system. Delay is computed as a heuristic function from a plurality of variables, such as disk head response times, time allotted for rebuild, number of rebuild threads, drive behavior, rebuild IO profile, host IO profile including workload and locality, and a timeline of sequenced events, which in one preferred embodiment cycles every 70 seconds.

Abstract: A controller is provided that receives a single enclosure management (EM) serial bit stream from an expander or other device and divides the EM serial bit stream into multiple EM serial bit streams for delivery to multiple respective midplanes or backplanes. In this way, a separate EM serial bit stream is provided to each midplane or backplane without having to increase the number of ports that are available on the expander or other device that interfaces with the backplane or midplane.

Abstract: A controller is provided that receives a single enclosure management (EM) serial bit stream from an expander or other device and divides the EM serial bit stream into multiple EM serial bit streams for delivery to multiple respective midplanes or backplanes. In this way, a separate EM serial bit stream is provided to each midplane or backplane without having to increase the number of ports that are available on the expander or other device that interfaces with the backplane or midplane.

Abstract: The present disclosure is directed to a system and method for monitoring drive health. A method for monitoring drive health may comprise: a) conducting a predictive fault analysis for at least one drive of a RAID; and b) copying data from the at least one drive of the RAID to a replacement drive according to the predictive fault analysis. A system for monitoring drive health may comprise: a) means for conducting a predictive fault analysis for at least one drive of a RAID; and b) means for copying data from the at least one drive of the RAID to a replacement drive according to the predictive fault analysis.

Abstract: The present disclosure is directed to a system and method for monitoring drive health. A method for monitoring drive health may comprise: a) conducting a predictive fault analysis for at least one drive of a RAID; and b) copying data from the at least one drive of the RAID to a replacement drive according to the predictive fault analysis. A system for monitoring drive health may comprise: a) means for conducting a predictive fault analysis for at least one drive of a RAID; and b) means for copying data from the at least one drive of the RAID to a replacement drive according to the predictive fault analysis.