Abstract: Communications between a host system and a storage system may be restricted to a single I/O path, at least temporarily, without manually manipulating physical connections to the host system and/or storage system or manually data structures defining I/O connectivity. In response to a communication to maintain only a first permitted I/O path between a host system and a storage system, I/O communications may be prevented on any I/O paths between the host system and the storage system, except for the first permitted I/O system, without modifying the definition of any permitted I/O paths on the storage system. One or more fields may be included in entries of a data structure that defines permitted I/O paths, the fields specifying whether an I/O path should be allowed to, or prevented from, carry communications between a host system and the storage system, at least temporarily.

Abstract: In response to a target port group state query from a host, the storage arrays that present a replicated volume to the host aggregate port group state of the storage arrays into a single logical target port group state that is provided to the host. The storage array that receives the query from the host may prompt other storage arrays to provide target port group state and combine the responses from all storage arrays. Port IDs may be translated into unique port IDs so that the logical target port group state does not include repeated port IDs.

Abstract: Techniques for processing I/O operations may include: receiving, an I/O operation including a tag value denoting a process of a database application that issued the I/O operation; determining, in accordance with the tag value, whether the I/O operation is directed to a data file storing content of a database or a log file of recorded operations of the database; and responsive to determining the I/O operation is directed to a data file storing content of the database, performing processing including: determining a current configuration setting of the database that indicates whether the database is configured for use with the database application as an in-memory database; and determining, in accordance with current configuration setting of the database, a first service level objective for the I/O operation, wherein the first service level objective for the I/O operation is a default service level objective or a revised service level objective.

Abstract: Techniques for determining connectivity may include: defining predetermined configurations, each including a predetermined zoning configuration of a network and selection criteria indicating when to transition into and activate the predetermined configuration; loading the predetermined configurations; activating a first of the predetermined configurations that includes a first predetermined zoning configuration and first selection criteria; receiving current I/O workload and/or performance information for the network; determining whether the current I/O workload and/or performance information for the network matches second selection criteria associated with a second of the predetermined configurations that is different from the first predetermined configuration currently activated; and responsive to determining the current I/O workload and/or performance information matches the second selection criteria, activating the second predetermined configuration that is different from the first predetermined configura

Abstract: Systems and methods for replicating data from storage. Snapshots are taken on a consistency group of volumes and are stored in snapshot volumes. Changes to the data stored in the volumes are identified from the snapshots and the changes are written to a journal. The journal allows the changes to be replicated to a virtual replication system and a physical replication system. The journal can be replicated to different systems, including physical and virtual systems, by exposing the same journal in different manners.

Abstract: Systems and methods for replicating data from storage. Snapshots are taken of the volumes in physical storage. The snapshot volumes are exposed to a virtual replication system. Using the snapshots, differential or changed data can be identified. The identified data is then replicated by the virtual replication system to a remove virtual replication system.

Abstract: A host device is configured to communicate over a network with a storage system comprising a plurality of storage devices. The host device comprises a multi-path input-output (MPIO) driver configured to control delivery of input-output (IO) operations from the host device to the storage system over selected ones of a plurality of paths through the network. The MPIO driver is further configured to determine IO processing performance for each of at least a subset of the paths, and to dynamically adjust a path selection algorithm utilized in selecting particular ones of the paths for delivery of the IO operations from the host device to the storage system based at least in part on the determined performance. For example, dynamically adjusting a path selection algorithm illustratively comprises activating a particular one of a plurality of distinct path selection algorithms available to the MPIO driver and/or adjusting one or more parameters of a given path selection algorithm.

Abstract: Techniques for protecting information may include: exposing a logical device of a data storage system to a host, wherein the logical device has an attribute identifying the logical device as a stealth device having accessibility controlled by the data storage system based on commands issued over a control path, wherein the logical device has a mode indicating whether the logical device is accessible to the host; sending, from the host to the data storage system, a write command that writes first data on the logical device when the mode indicates the logical device is accessible to the host; and subsequent to said sending, issuing a command over the control path to the data storage system, wherein the command sets the mode of the logical device to inaccessible indicating the logical device is not accessible to the host.

Abstract: A storage system may maintain a purge counter for one or more logical storage units. When an instruction is received to perform an operation that will modify data across the one or more logical storage units, the purge counter may be incremented. One or more host systems implementing host caching may periodically poll the storage system to determine the purge counter value. When the current value of the purge counter value is different than a previously polled purge counter value recorded on a host system, the host system may purge from its host cache any entries for logical storage units associated with the purge counter. The data storage system may not execute the data modification instruction until it receives acknowledgement from all host systems caching data affected by the modification instruction that the host system has purged any host cache entries corresponding to the LSUs affected by the modification operation.

Abstract: Physical storage devices may be managed for spontaneous de-staging from a cache, for example, by determining a background task threshold (UBTT), and controlling one or more physical storage devices to use the UBTT instead of the VBTT in determining when to enter background task mode. The determined UBTT may be less than the VBTT, which may cause the physical storage device to enter into background task mode earlier, which means that background tasks like garbage collection and write leveling may be performed more frequently. An ability to turn on and turn off management of physical storage devices for spontaneous de-staging of a cache may be provided. It may be desirable to turn off physical storage device management for spontaneous de-staging, for example, during peak workload hours, to prevent physical storage devices from entering into background task mode more frequently during certain times.

Abstract: Multiple virtual host ports corresponding to a same physical host port may be determined by or on behalf of a storage system, for example, in response to logging the one or more virtual host ports into the storage system. For one or more virtual host ports, it may be determined whether the virtual host port is connected to a same fabric port as another virtual host port, where a fabric port is a port of a fabric configured to connect to a virtual host port. If two virtual host ports are determined to be connected to a same fabric port, it may be concluded that the two virtual host ports correspond to (e.g., share) a same physical host port. One or more actions may be taken on a storage network based at least in part on a determination that two virtual host ports are sharing a same physical host port.

Abstract: Embodiments of the present disclosure relate to traffic class management of NVMe (non-volatile memory express) traffic. One or more input/output (I/O) operations are received at a device interface coupled to one or more storage devices of a storage array. A service level (SL) corresponding to each of the one or more I/O operations is determined. Each of the one or more I/O operations is transmitted to the one or storage devices over a virtual channel of a set of virtual channels based on the determined SL corresponding to each of the one or more I/O operations.

Abstract: Service level objectives (SLOs) defined for a storage system are associated with VMs running on hosts. For an I/O operation for a virtual machine (VM) running on a host system, storage processing is performed on the I/O operation in accordance with the SLO defined for the VM. The same storage system-defined SLOs may be applied to VMs running on multiple host systems. SLOs may be maintained by the storage array and shared with one or more host systems in I/O communication with the storage system. SLOs may be defined using a user interface of a storage system, host system, virtualizer control station or other component of a storage network, and communicated to the storage system, which may maintain the SLOs, and may disseminate them to one or more hosts. The SLOs then may be associated with VMs running on the hosts and tagged to I/O communications corresponding to the VMs.

Abstract: Service level objectives (SLOs) defined for a storage system are associated with virtual machines running on hosts. For an I/O operation for a virtual machine (VM) running on a host system, storage processing is performed on the I/O operation in accordance with the SLO defined for the VM. The same storage system-defined SLOs may be applied to VMs running on multiple host systems. SLOs may be maintained by the storage array and shared with one or more host systems in I/O communication with the storage system. SLOs may be defined using a user interface of a storage system, host system, virtualizer control station or other component of a storage network, and communicated to the storage system, which may maintain the SLOs, and may disseminate them to one or more hosts. The SLOs then may be associated with VMs running on the hosts and tagged to I/O communications corresponding to the VMs.

Abstract: Communications between a host system and a storage system may be restricted to a single I/O path, at least temporarily, without manually manipulating physical connections to the host system and/or storage system or manually data structures defining I/O connectivity. In response to a communication to maintain only a first permitted I/O path between a host system and a storage system, I/O communications may be prevented on any I/O paths between the host system and the storage system, except for the first permitted I/O system, without modifying the definition of any permitted I/O paths on the storage system. One or more fields may be included in entries of a data structure that defines permitted I/O paths, the fields specifying whether an I/O path should be allowed to, or prevented from, carry communications between a host system and the storage system, at least temporarily.

Abstract: Techniques for transmitting data may include: receiving, at a host, an initiator data transfer rate indicating a communication rate at which an initiator port of the host communicates over a first path using a communications fabric with a target port of a data storage system; receiving, at the host, a target data transfer rate indicating a communication rate at which the target port of the data storage system communicates over the first path using the communications fabric with the initiator port of the host; determining, at the host, whether the initiator data transfer rate and the target data transfer rate are different; and responsive to determining that the initiator data transfer rate and the target data transfer rate are different, performing processing that limits a rate at which data is transmitted between the initiator and target ports in accordance with the initiator and target data transfer rates.

Abstract: Techniques for processing I/O operations may include: receiving an I/O operation directed to a logical device having an associated service level objective with a target I/O response time; performing first processing that determines an estimated response time for the I/O operation, and determining, based on the estimated response time for the I/O operation and the associated service level objective, whether to delay the I/O operation by an additional amount of time thereby increasing a measured response time for the I/O operation by the additional amount. The first processing may include determining a fixed baseline amount of time for the I/O operation; determining a cumulative amount of time estimated to service pending I/O operation queued for service prior to the I/O operation; and determining an expected service time estimated for servicing the I/O operation. Moving averages maintained for different I/O types and sizes may be used in determining I/O service times.

Abstract: Storage-based slow drain detecting and automated resolution is provided herein. A data storage system as described herein can include a memory that stores computer executable components and a processor that executes computer executable components stored in the memory. The computer executable components can include a switch query component that obtains a host transfer rate negotiated between a host device and a network switch from a host-connected port of the network switch; a comparison component that compares the host transfer rate to an array transfer rate negotiated between the network switch and a storage array; and a rate limiter component that limits a data transfer from the storage array to the host device to the host transfer rate in response to the host transfer rate being less than the array transfer rate.

Abstract: In a computer network in which a data storage array maintains data for at least one host computer, the host computer provides sequential access hints to the storage array. A monitoring program monitors a host application running on the host computer to detect generation of data that is likely to be sequentially accessed by the host application along with associated data. When the host application writes such data to a thinly provisioned logical production volume the monitoring program prompts a multipath IO driver to generate the sequential access hint. In response to the hint the storage array allocates a plurality of sequential storage spaces on a hard disk drive for the data and the associated data. The allocated storage locations on the hard disk drive are written in a spatial sequence that matches the spatial sequence in which the storage locations on the production volume are written.

Abstract: A trust relationship may be established between a host system and a storage system. An asymmetric key pair including a private key unique to a host system and a public key may be generated. During provisioning of the host system to the storage system, the host system may send the public key to the storage system. The storage system may be configured to record the public key for the host system, for example, in a masking table that defines I/O connectivity for logical storage units between a host system and the storage system. The public key may be used later to validate the host system to the storage system. The private key may be stored on the host system and be unreadable, or may be encrypted with an unreadable encryption key stored on the host system.