Abstract: Bandwidth consumption and/or an I/O transmission rate on an I/O path between a port of a storage system and a physical host port may be managed, including determining when multiple virtual host ports correspond to (i.e., are mapped to) a same physical host port. This virtual host port mapping information may be used to more accurately determine bandwidth consumption and I/O transmission rates on I/O connections along an I/O path including the physical host port, and to adjust the bandwidth consumption and/or I/O transmission rate on one more of these I/O connections according to bandwidth thresholds and I/O count thresholds defined for the I/O path (e.g., for the Physical host port of the I/O path).

Abstract: An apparatus comprises at least one processing device that is configured to send write requests to a first storage system. The first storage system is configured to participate in a replication process in which data associated with the write requests is replicated from the first storage system to a second storage system that is separate from the first storage system. The at least one processing device is further configured to receive from the first storage system an indication of a write pressure condition arising in the second storage system and relating to replication of the data associated with the write requests from the first storage system to the second storage system, and to at least temporarily limit a manner in which additional write requests are sent to the first storage system responsive to the received indication of the write pressure condition arising in the second storage system.

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: An apparatus comprises at least one processing device that is configured to control delivery of input-output operations from a host device to a 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 at least one processing device is further configured to identify a particular one of the initiators that comprises multiple virtual initiators having respective virtual identifiers, to determine a negotiated rate of the particular initiator, to determine a negotiated rate of a corresponding one of the targets, and to limit amounts of bandwidth utilized by the multiple virtual initiators in communicating with the corresponding target based at least in part on the negotiated rate of the particular initiator and the negotiated rate of the corresponding target.

Abstract: A host device comprises a processor coupled to a memory. The host device is configured, for each of a plurality of initiators of the host device from which write operations are sent to a storage system for processing, to repeatedly send to the storage system a command to obtain from the storage system write pressure information maintained by the storage system for that initiator, and responsive to the write pressure information obtained from the storage system for a corresponding one of the initiators indicating that the corresponding initiator is associated with a write pressure condition, to at least temporarily reduce a rate at which the write operations are sent from the corresponding initiator to the storage system. The operations of repeatedly sending the command, and at least temporarily reducing the rate, are illustratively performed by at least one multi-path input-output driver of a multi-path layer of the host device.

Abstract: Techniques for processing I/O operations may include: receiving an I/O having an associated expected execution time (EET) and I/O service level; selecting, in accordance with the EET and service level of the I/O, a first I/O queue from multiple pending I/O queues; inserting the I/O into the first I/O queue; and performing I/O shifting. I/O shifting may include shifting I/Os from one pending I/O queue to another that is ranked immediately higher than the one pending I/O queue. The multiple I/O queues may be ranked from a highest priority queue to a lowest priority queue. I/O shifting may shift I/Os from the highest priority queue to execution and shifting I/Os from another queue into the highest priority queue. I/O shifting is subject to remaining credits available of the multiple I/O queues and time distance between source and target queues.

Abstract: Techniques for processing I/O operations may include: receiving an I/O having an associated expected execution time (EET) and I/O service level; selecting, in accordance with the EET and service level of the I/O, a first I/O queue from multiple pending I/O queues; inserting the I/O into the first I/O queue; and performing I/O shifting. I/O shifting may include shifting I/Os from one pending I/O queue to another that is ranked immediately higher than the one pending I/O queue. The multiple I/O queues may be ranked from a highest priority queue to a lowest priority queue. I/O shifting may shift I/Os from the highest priority queue to execution and shifting I/Os from another queue into the highest priority queue. I/O shifting is subject to remaining credits available of the multiple I/O queues and time distance between source and target queues.

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: A storage array in one embodiment is configured to communicate over one or more networks with a plurality of host devices. The storage array is further configured to detect process tags assigned to respective input-output operations by a given one of the host devices, the process tags being of at least first and second distinct types so as to distinguish at least respective first and second distinct processes generating corresponding ones of the input-output operations on the given host device. Responsive to a particular one of the detected process tags being of the first type, the storage array provides a first level of priority for processing of the corresponding input-output operation, and responsive to a particular one of the detected process tags being of the second type, the storage array provides a second level of priority different than the first level of priority for processing of the corresponding input-output operation.