Abstract: A host system may include a computational processing unit implemented using hardware and a hardware virtualizing and remote sharing (HVRS) server that virtualizes and shares the computational processing unit with other host systems, where the host system is directly connected to an internal fabric of a storage system. A storage system interface (SSI) of the host system may be directly connected to the internal fabric of the storage system and also directly connected to a same peripheral device interconnect as the CPU, the computational processing unit and/or other hardware resources of the host system. The SSI may communicate with storage resources of the storage system using remote direct memory access (RDMA) and zero-copy technologies. Such a host system may provide the storage capacity and data protection services of a storage system at relatively fast speeds e.g., comparable to non-volatile RAM on a host system configured for use as persistent memory.

Abstract: Snapshots are created on replicated storage systems R1 and R2 in a manner resulting in identical snapshots being generated on R1 and R2. In response to an instruction to create a snapshot on a storage system (R1 and/or R2), command-phase write operations (CWOs) are held and data-phase write operations (DWOs) are completed on the storage system before the snapshot is created. Determining that DWOs includes querying processes, and using information, available on the storage system, by which a state of a write operation—e.g., whether the write operation is a DWO and when the DWO completes—may be determined. A CWO queue may be maintained on the storage system for tracking the status of CWOs. A DWO queue may be maintained on the storage system for tracking DWOs, to determine DWOs when the snapshot is created, and track their processing, including when they are completed.

Abstract: Information pertinent to a connectivity issue reported by a switch may be determined, compiled and reported; and action may be taken autonomously to address the connectivity issue based on the information. The additional information may be determined by the storage system, including querying a switch in response to the switch notifying the storage system of the I/O error, and the storage system accessing one or more data structures to determine additional information. The storage system may cause I/O communications on the I/O path to be at least temporarily diverted. For example, in response to receiving an I/O request on the I/O path corresponding to the connectivity issue, the storage system may send a communication to the host system that causes the host system not to send additional I/O requests on the I/O path, at least temporarily, as described in more detail elsewhere herein.

Abstract: In response to receiving a read metadata request from the host system for a data portion, the storage system may determine a status and location of the data portion, including determining whether the data portion is in a cache of the storage system. If the data portion is in the cache, the storage system may send a response that includes the data portion itself along with the status and location of the data portion. If the data portion is not in the cache, the storage system may send a response to the read metadata request that includes the status and location of the data portion, but not the data portion itself. The host system may be configured to determine whether the data portion has been returned with the metadata response, and if so, refrain from sending a separate data request, for example, to retrieve the data portion from cache.

Abstract: Techniques for memory management may include: allocating, from an allocation pool, buffers for logs used by processing cores; recording messages in the logs for the processing cores; responsive to filling a first buffer included in a first log used to record messages for a first of the plurality of processing cores, allocating a second buffer of the allocation pool for the first log; adding the second buffer to the first list of buffers for the first log; and adding the first buffer, that is included in the first list for the first log, to the allocation pool, wherein after adding the first buffer to the allocation pool, the first buffer is included in the first list of buffers for the first log and also included in the allocation pool. The buffers may be included in a distributed global memory portion of the same computing module as the processing cores.

Abstract: An apparatus comprises at least one processing device that includes a processor coupled to a memory. The processing device is configured to control delivery of input-output (IO) operations from a host device to at least one storage system over selected ones of a plurality of paths through a network, wherein the paths are associated with respective initiator-target pairs, the initiators being implemented on the host device and the targets being implemented on the storage system. The processing device is further configured to identify one or more of the plurality of paths that each exhibits at least a threshold amount of mismatch between a negotiated rate of its initiator and a negotiated rate of its target, and to modify path selection in the host device to at least temporarily avoid selecting the one or more identified paths. The processing device illustratively comprises at least a portion of the host device.

Abstract: In a data processing system having multiple production hosts, each with a backup agent, interfaced to a storage array and to a backup server, an array I/O priority engine on the storage array establishes and enforces I/O priorities for I/O backup and production communications with the array to ensure that backup does not consume a disproportionate CPU processing and array bandwidth load or disrupt more critical production processing.

Abstract: An apparatus comprises at least one processing device that includes a processor and a memory coupled to the processor. The at least one processing device is configured to receive storage access protocol commands directed by one or more host devices to storage devices of a storage system over a storage area network, to generate statistics relating to the received storage access protocol commands, to process the generated statistics in a machine learning system trained to recognize anomalous access patterns to the storage devices over the storage area network, and to generate an alert indicative of an access anomaly based at least in part on the processing of the generated statistics in the machine learning system. A multi-path input-output (MPIO) driver of the one or more host devices may be provided with the alert and configured to initiate one or more remediation actions responsive to the alert.

Abstract: Techniques for configuring paths for transmitting I/O operations may include: configuring a first path over which logical devices are exposed over a first port of a data storage system to a second port of a host, wherein the logical devices include a first logical device having a first service level objective and a second logical device having a second service level objective denoting a lower service level than the first service level objective; determining whether there is a service level objective violation of the first service level for the first logical device; and responsive to determining there is a service level objective violation for the first logical device, performing first processing that exposes the first logical device and the second logical device over different ports of the data storage system. Masking information may indicate which logical devices are exposed over which data storage system ports to which host ports.

Abstract: Described herein are systems and techniques for determining when excessive I/O response times are not the fault of a storage port, but rather are caused by other factors or components on a storage network, for example, over-utilization of a host port. For one or more host ports and/or storage ports, a payload idle time (PIT) may be determined for each I/O operation, the PIT being the amount of time during which a storage port is waiting for a host port to be ready to send or receive data of the respective I/O operation. It may be determined whether one or more of the PITs includes an excessive idle time (EIT), where the EIT may be an amount of the PIT that is more than a predefined acceptable amount of time. The cause of the EIT may be determined.

Abstract: Embodiments of the present disclosure relate to traffic class management of NVMe (non-volatile memory express) traffic. One or more virtual controllers for at least one host adapter (HA) of a storage device are generated. Each virtual controller is assigned a unique controller identifier (ID) Additionally, one or more input/output (IO) queues for each virtual controller are established. Further, IO workloads are processed via each IO queue.

Abstract: Writes to one or more physical storage devices may be blocked after a certain storage consumption threshold (WBT) for each physical storage device. A WBT for certain designated physical storage devices may be applied in addition to, or as an alternative to, determining and applying a user-defined background task mode threshold (UBTT) for certain designated physical storage devices. In some embodiments, the WBT and UBTT for a physical storage device designated for spontaneous de-staging may be a same threshold value. Write blocking management may include, for each designated physical storage device, blocking any writes to the designated physical storage device after a WBT for the designated physical storage device has been reached, and restoring (e.g., unblocking) writes to the designated physical storage device after storage consumption on the physical storage device has been reduced to a storage consumption threshold (WRT) lower than the WBT.

Abstract: An apparatus comprises at least one processing device that includes a processor coupled to a memory. The processing device is configured to control delivery of input-output (IO) operations from a host device to at least first and second storage systems over selected ones of a plurality of paths through a network, the first and second storage systems being arranged in an active-active configuration relative to one another. The processing device is further configured to identify one or more logical storage devices that are each accessible via at least first and second different ones of the paths to respective ones of the first and second storage systems, and to modify path selection for IO operations directed to the one or more identified logical storage devices relative to path selection for IO operations directed to one or more other logical storage devices. The processing device illustratively comprises at least a portion of the host device.

Abstract: Bandwidth consumption for IO paths between a storage system and host may be managed. It may be determined whether there is congestion on a front-end port (FEP) link. For example, the storage system may monitor for a notification from the switch in accordance with a Fibre Channel (FC) protocol. If a notification is received indicating congestion on an FEP link, the bandwidth thresholds (BWTs) for one or more IO paths between the storage system and one or more hosts that include the FEP link may be reduced. The host port BWTs may continue to be reduced until a congestion notification communication has not been received for a predetermined amount of time, in response to which the host port BWTs for one or more host port links on IO paths that include the FEP link may be increased. Similar techniques may be employed for an FEP link determined to be faulty.

Abstract: An apparatus in one embodiment comprises a host device configured to communicate over a network with a storage system comprising a plurality of storage devices. The host device comprises a set of input-output queues and a multi-path input-output driver configured to select input-output operations from the set of input-output queues for delivery to the storage system over the network. The multi-path input-output driver is further configured to send a predetermined command to the storage system over each of a plurality of paths from the host device to the storage system, to monitor a response time for the predetermined command on each of the paths, and to detect a performance issue with at least a given one of the paths based at least in part on the monitored response time. The predetermined command illustratively comprises a Small Computer System Interface (SCSI) “immediate” command of a particular type, such as a Test Unit Ready (TUR) command.

Abstract: Techniques for transmitting data may comprise: receiving a first data transfer rate indicating a communication rate at which a first entity communicates with a second entity over a communications fabric; receiving a second data transfer rate indicating a communication rate at which the second entity communicates with the first entity over the communications fabric; and performing first processing to send first data from the first entity to the second entity over the communications fabric, said first processing including: determining whether the first data transfer rate is greater than the second data transfer rate; and responsive to determining the first data transfer rate is greater than the second transfer rate, performing second processing by the first entity that controls and limits, in accordance with the second data transfer rate, a rate at which the first data is transmitted from the first entity to the second entity.

Abstract: Embodiments are described for a multi-node file system, such as a clustered or distributed file system, with a file system buffer cache and an additional host-side tier non-volatile storage cache such as 3DXP storage. Cache coherency can be maintained by one of three models: (i) host-side tier management, (ii) file system management, or (iii) storage array management. performing a storage tier-specific file system action in a file system that comprises a namespace that spans multiple tiers of storage.

Abstract: Trust may be maintained between a storage system and a host system by the host system validating its identity to the storage system. The storage system may instruct the host system to validate itself by setting a validation flag on the storage system. The host system may be configured to determine whether the validation flag is set. If the host system determines that the validation flag is set, the host system then may read a test string from the storage system. The host system may encrypt the test string using a private key, and send the encrypted test string to the storage system. The storage system may decrypt the encrypted string using a public key it previously received from the host system. The decrypted test string then may be compared against the original test string generated by the storage system.

Abstract: A processing node of a storage system may determine that a host system is implementing a cache-slot aware, round-robin IO distribution algorithm (CA-RR). The processing node may be configured to determine when a sufficient number of sequential IOs will be received to consume a cache slot of the a processing node. If the processing node knows that the host system is implementing CA-RR, then, in response to determining the sufficient number, the processing node may send a communication informing the next processing node about the sequential cache slot hit. If the sequential IO operation(s) are read operation(s), the next processing node may prefetch at least a cache-slot worth of next consecutive data portions. If the sequential IO operation(s) are write operation(s), then the next processing node may request allocation of one or more local cache slots for the forthcoming sequential write operations.

Abstract: Embodiments are described for dynamically allocating and reallocating system resources between production work tasks and administrative tasks using policies. A resource monitor continuously monitors all resources in a computing system, and whether the resources are used for production work or administrative tasks. A policy can define resources needed to execute an administrative task and conditions which can be used to determine whether or not the administrative command is allocated the resources, even at the expense of a negative impact to production work.