Abstract: Data encrypted using a first device-specific key of a first host device is written to a first logical storage device of a storage system. The storage system generates a copy of the first logical storage device, and associates the copy of the first logical storage device with a second logical storage device of the storage system. Data encrypted using a second device-specific key of a second host device is written to the second logical storage device of the storage system. Responsive to a request from the second host device for particular data of the second logical storage device, the storage system determines if the particular data was encrypted using the first key or the second key, and provides the second host device with the particular data and an indication of a result of the determination.

Abstract: A temporal correlation may be determined between times specified according to different time standards on different storage network components. A host system may poll a storage system periodically. In response to each poll request, the storage system may respond with the current time on the storage system (CST) according to the time standard of the storage system. The host system may store temporal correlation information (TCI) associating the CST and the current time on the host system (CHT) according to the time standard of the host system. A data structure (TCT) may be provided, where each entry may specify TCI for a CST/CHT pair, the TCI including the CST, CHT and other information corresponding to the temporal correlation between the pair. The TCI may be used to correlate the time of a phenomenon according to the host system time standard to a time according to the storage system time standard.

Abstract: At least one processing device is configured to register a logical storage device of a storage system for a first set of paths associated with a first access protocol using a host identifier, to send a first reservation command in the first access protocol over each of the paths in the first set of paths, to register the logical storage device of the storage system for a second set of paths associated with a second access protocol using the same host identifier used in registering the logical storage device for the first set of paths, to receive an additional reservation command in the first access protocol, and responsive to receipt of the additional reservation command in the first access protocol, to translate the additional reservation command to the second access protocol, and to send the additional reservation command in the second access protocol to the storage system.

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: An apparatus comprises a host device configured to communicate over a network with a storage system. The host device establishes a migration session in the host device for migration of a source logical storage device accessible utilizing a first access protocol to a target logical storage device accessible utilizing a second access protocol, and migrates the source logical storage device to the target logical storage device utilizing a multi-path layer of the host device. The multi-path layer maintains separate device identities for the respective source and target logical storage devices in conjunction with the migration session but presents a corresponding composite device having a single device identity to one or more applications executing on the host device. The multi-path layer translates one or more commands directed to the composite device in the first access protocol to one or more commands in the second access protocol.

Abstract: A host server in a server cluster has a memory allocator that creates a dedicated host application data cache in storage class memory. A background routine destages host application data from the dedicated cache in accordance with a destaging plan. For example, a newly written extent may be destaged based on aging. All extents may be flushed from the dedicated cache following host server reboot. All extents associated with a particular production volume may be flushed from the dedicated cache in response to a sync message from a storage array.

Abstract: When a read request for the data portion is received from an application executing on a host, the host may determine whether the data portion is in host cache, and if so, whether the logical storage unit of the data portion is shared by another host system. If there is another host system sharing the logical storage unit, a latest version stored on the storage system may be determined and compared to the version stored in the host cache. If the version in the host cache is the same as the latest version stored on the storage system, the data portion may be retrieved from the host cache. If the version in the host cache is not the latest version stored on the storage system, the data portion may be retrieved from the storage system, and the host cache may be updated with the latest version of the data portion.

Abstract: Techniques for processing I/O operations in a data storage system may include: receiving I/O operations directed to a logical device associated with a service level specifying a target I/O response time goal; receiving a input identifying whether to calculate an observed I/O response time for the logical device using only an internal processing time associated with processing performed within the data storage system when servicing I/O operations directed to the logical device; determining, in accordance with the input and the I/O operations directed to the logical device, the observed I/O response time for the logical device; determining a service level violation for the first logical device whereby the observed I/O response time violates the service level; and responsive to determining the service level violation whereby the observed I/O response time violates the service level, performing processing to alleviate or remove the first service level violation.

Abstract: A method comprises associating a first logical storage device with a first host device, wherein data encrypted using a private key of the first host device is written to the first logical storage device, generating a copy of the first logical storage device, associating the copy of the first logical storage device with a second logical storage device, wherein data encrypted using a private key of a second host device is written to the second logical storage device, and providing the second host device with access to an encrypted version of a public key of the first host device, encrypted using a public key of the second host device, to allow the second host device to obtain the public key of the first host device. The second host device can thereby access particular data of the second logical storage device written using the private key of the first host device.

Abstract: Techniques for processing I/O operations may include: issuing, by a process of an application on a host, an I/O operation; determining, by a driver on the host, that the I/O operation is a read operation directed to a logical device used as a log to log writes performed by the application, wherein the read operation reads first data stored at one or more logical addresses of the logical device; storing, by the driver, an I/O flag in the I/O operation, wherein the I/O flag has a first flag value denoting an expected read frequency associated with the read operation; sending the I/O operation from the host to the data storage system; and performing first processing of the I/O operation on the data storage system, wherein said first processing includes using the first flag value in connection with caching the first data in a cache of the data storage system.

Abstract: An apparatus in one embodiment comprises at least one processing device. The at least one processing device is configured to monitor performance of respective ones of a plurality of paths for accessing a logical storage device, and responsive to detection of at least one specified condition in the monitored performance relating to at least a subset of the paths, to move at least one application from a first container that utilizes a first access protocol to access the logical storage device to a second container that utilizes a second access protocol different than the first access protocol to access the logical storage device. For example, in some embodiments, the at least one processing device is configured to move an application from first container that utilizes a SCSI access protocol to a second container that utilizes an NVMe access protocol, and vice versa, responsive to detected performance issues.

Abstract: Techniques for detecting and managing target port overloads due to host initiator or path failures may include: receiving I/Os from initiators of a host at target ports of a data storage system; determining initiator workloads for the initiators; determining target workloads for the target ports; determining that a first of the initiators of the host is a failed initiator that has stopped sending I/Os to the data storage system, wherein the first initiator has a first of the initiator workloads; determining, in accordance with the first initiator workload, revised target workloads for the target ports; determining, in accordance with revised target workloads, whether any of the target ports is expected to be overloaded; and responsive to determining that at least one of the target ports is expected to be overloaded, performing a corrective action to alleviate or reduce an overloaded workload condition expected for the at least one target port.

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: A method includes designating one or more particular portions of a storage volume of a storage system for inclusion in a sub-volume snapshot. The method further includes generating the sub-volume snapshot as a point-in-time copy that includes the one or more designated portions of the storage volume and excludes one or more non-designated portions of the storage volume. The method is performed by at least one processing device comprising a processor coupled to a memory. The storage volume illustratively comprises a logical unit of a virtual machine file system, with the one or more designated portions of the logical unit of the virtual machine file system illustratively comprising at least one virtual machine storage drive file of the virtual machine file system. In some embodiments, a bitmap or other data structure is maintained for the storage volume with particular entries in the data structure corresponding to respective ones of the portions.

Abstract: An apparatus comprises at least one processing device comprising a processor and a memory. The at least one processing device is configured to provision a first logical device on a first storage system, to configure the first logical device to support replication from the first storage system to a second storage system, and to initiate generation of a remote backup copy of a second logical device on the second storage system. In conjunction with performance of a verification process for the remote backup copy of the second logical device, the at least one processing device is configured to cause the first logical device to be paired with the remote backup copy of the second logical device, and to mount the first logical device so as to permit performance of the verification process for the remote backup copy utilizing data obtained from the remote backup copy via the first logical device.

Abstract: Memory of a storage system is made available (i.e., exposed) for use as host memory of a host, for example, as an extension of the main memory of the host. The host may be directly connected to an internal fabric of the data storage system. Portions of the storage system memory (SSM) may be allocated for use as host memory, and this may be communicated to the host system. The host OS and applications executing thereon then may make use of the SSM as if it were memory of the host system, for example, as second-tier persistent memory. The amount of SSM made available may be dynamically increased and decreased. The SSM may be accessed by the host system as memory; i.e., in accordance with memory-based instructions, for example, using remote direct memory access instructions. The SSM may be write protected using mirroring, vaulting and other techniques.

Abstract: Estimating maintenance for a storage system includes accessing a model that outputs time and materials estimates based on input configuration data, providing configuration data of the storage system to the model, and obtaining an estimate of maintenance time and materials based on the configuration data provided to the model. The model may be provided by a neural network, which may be a self-organized map. Weights of neurons of the self-organized map may be initialized randomly. The model may be initially configured using training data that may include an I/O load of the storage system, memory size of the storage system, a drive count of the storage system, and/or size and parameter information corresponding to hardware being added for the maintenance operation. The training data may include actual time and materials for prior storage system maintenance operations used for the training data. The model may be provided on the storage system.

Abstract: An apparatus in one embodiment stores a first version of an operating system data structure comprising a first identifier of a logical storage device associated with a first access protocol, and in conjunction with migration of the logical storage device from utilization of the first access protocol to utilization of a second access protocol, temporarily continues to present information from the first version of the operating system data structure in response to one or more requests relating to the logical storage device, obtains a second identifier of the logical storage device associated with the second access protocol, stores a second version of the operating system data structure comprising the second identifier of the logical storage device associated with the second access protocol, and switches from presenting information from the first version of the operating system data structure to presenting information from the second version of the operating system data structure.

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: A storage system comprises a plurality of storage devices, and is configured to establish a production drive group comprising a first subset of the storage devices, using a first firmware-level configuration process, and to establish a stealth drive group comprising a second subset of the storage devices, using a second firmware-level configuration process, the storage devices of the stealth drive group thereby being separated at a firmware level of the storage system from the storage devices of the production drive group. The storage system is further configured to copy data of one or more logical storage volumes from the production drive group to the stealth drive group, and responsive to completion of the copying of the data of the one or more logical storage volumes from the production drive group to the stealth drive group, to initiate a firmware-level reconfiguration process for the storage devices of the stealth drive group.