Abstract: Improved mechanisms and techniques for recording and aggregating trace information from multiple computing modules of a storage system may be provided. On a storage system having multiple computing modules, where each computing module has multiple processing cores, processing cores may record trace information for I/O operations in dedicated local memory—i.e., memory in the same computing module as the processing core that is dedicated to the computing module. One of the processing cores may be configured to aggregate trace information from across multiple computing modules into its dedicated local memory by accessing trace information from the dedicated local memories of the other computing modules in addition to its own. The aggregated information in one dedicated local memory then may be analyzed for functionality and/or performance and additional action taken based on the analysis.

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: 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: 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: 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: A storage system in one embodiment comprises at least one storage array comprising a plurality of storage devices. The storage array is configured to communicate over one or more networks with a plurality of host devices. The storage array is further configured to receive one or more commands from a given one of the host devices directing that a particular user-defined name be assigned to a particular one of the storage devices, and responsive to receipt of the one or more commands, to determine if any other user-defined name is already assigned to the particular storage device, and if there is no other user-defined name already assigned to the particular storage device, to assign the particular user-defined name to the particular storage device and to store information characterizing the assignment of the particular user-defined name to the particular storage device in persistent memory of the storage array.

Abstract: An apparatus comprises a host device configured to communicate over a network with a storage system comprising a plurality of storage devices. The host device is further configured to execute multiple processes that generate input-output (IO) operations for delivery to the storage system. The host device comprises a multi-path input-output (MPIO) driver configured to store for each of one or more of the storage devices information specifying one or more of the processes executing on the host device that are permitted to access that storage device, and for each of at least a subset of the IO operations, to determine the particular storage device to which the IO operation is directed, to identify the process that generated the IO operation, and to control delivery of the IO operation based at least in part on whether or not the stored information indicates that the identified process is permitted to access the particular storage device.

Abstract: A method, system, and computer program product for measuring latency in storage area networks comprising receiving a command from a node at a first time by a target in a storage area network, evaluating the command by the target, and returning a reply to the node from the target at a second time, wherein a difference between the second time and the first time is less than a time period indicative of a processing delay in the target, wherein the reply is considered a good status reply.

Abstract: A distributed data storage system includes first and second data storage systems (DSSs) at respective sites and a cloud gateway at a third. The first DSS remotely mirrors data using synchronous and asynchronous channels both employing a block-based protocol (e.g., SCSI). The second DSS is connected to the synchronous channel to provide synchronous backup to the first DSS. The cloud gateway is connected to the asynchronous channel and has a cloud storage connection to a cloud storage system, the cloud storage connection using a wide area network interface and employing an object-based protocol. The cloud gateway (1) provides asynchronous backup to the first DSS via the asynchronous channel, and (2) uses the cloud storage connection to access object-based cloud data storage to store data of the asynchronous backup. The use of the cloud gateway and cloud storage system for an asynchronous third mirror enhances reliability/resiliency in a cost-effective manner.

Abstract: An apparatus 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 maintain payload size counters to track outstanding command payload for respective ones of a plurality of paths from the host device to the storage system, to detect an oversubscription condition relating to at least one of the paths based at least in part on values of one or more of the payload size counters, and to initiate one or more automated actions responsive to the detected oversubscription condition.

Abstract: An aspect includes determining, in response to an efficiency indicator associated with a destination disk array of a plurality of destination disk arrays, to relocate at least a portion of data currently on a source Logical Unit (LUN) of a source disk array of a plurality of source disk arrays to the destination disk array. The efficiency indicator represents an amount of data on the source LUN that also resides on the destination disk array. The destination disk array supports deduplication. An aspect also includes evaluating multiple destination LUNs of the destination disk array to relocate the data to based on the efficiency indicator and at least one capacity-based factor corresponding to the multiple destination LUNs, selecting one of the multiple destination LUNs to relocate the data based on results of the evaluating, and relocating the data from the source LUN to the selected one of the multiple destination LUNs.

Abstract: Techniques for performing data migration may include: receiving host information regarding hosts registered on a source data storage system; issuing registration commands from a host to a target data storage system; determining, at the target data storage system in accordance with the registration commands, a host registration table including a corresponding entry for the host, the corresponding entry denoting a host name for the host and initiators of the host that sent the registration commands; and determining a masking view for the host on the target data storage system, the masking view including an initiator group of the initiators of the host that sent the registration commands to the target data storage system, wherein the masking view is used by the target data storage system to determine whether to service received I/O operations.

Abstract: Techniques for processing I/O operations may include: selecting a logical device having at least one snapshot on a data storage system; sending, from a host to the data storage system, a first hint for a first write I/O operation directed to a first location on the logical device, wherein said sending the first hint is performed prior to the host sending the first write I/O operation to the data storage system; and responsive to receiving the first hint regarding the first write I/O operation to the first location of the logical device having at least one snapshot, performing preprocessing for the first write I/O operation. Hints may also be sent for I/O operations directed to a target device linked to a snapshot of the logical device. The data storage system may perform preprocessing for the I/O operations directed to the target device linked to the snapshot.

Abstract: An apparatus comprises a host device configured to communicate over a network with a storage system. The host device comprises a multi-path input-output driver configured to control delivery of input-output operations from the host device to the storage system over selected ones of a plurality of paths through the network. The multi-path input-output driver is further configured to collect information characterizing input-output patterns for each of a plurality of different applications executing on the host device, and to provide the collected information to a machine learning system. The machine learning system utilizes the collected information to generate one or more application predictions based at least in part on analysis of observed input-output patterns. The collected information in some embodiments comprises statistical distributions of numbers of input-output operations having payload sizes falling into specified ranges over a given time period.

Abstract: Determining an expected compression rate for a prospective process in a federated system includes obtaining compression rate data for existing processes in the federated system, compiling the compression rate data into a plurality of entries in a process name table according to process identifier, client, and industry, determining a specific entry in the process name table for an existing process that most closely matches the prospective process, and determining an expected compression rate of the prospective process based on the compression rate data for the specific entry. Compression rate data may be provided by a driver at host systems that sends compression rate information to a central repository. The central repository may be provided by a host system at a data center of the federated system. The compression rate data may use a sliding average that weighs the data more heavily to favor more recent data.

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: An apparatus comprises a host device configured to communicate over a network with a storage system. The host device comprises a plurality of host bus adaptors, and a multi-path input-output driver configured to control delivery of input-output operations from the host device to the storage system over selected ones of a plurality of paths through the network. The paths are associated with respective initiator-target pairs wherein each of the initiators comprises a corresponding one of the host bus adaptors and each of the targets comprises a corresponding one of a plurality of ports of the storage system. The host device monitors performance of the ports in processing input-output operations delivered thereto, detects an initiator-related condition based at least in part on the monitored performance, and automatically adjusts an assignment of one or more of the initiators to one or more of the targets based at least in part on the detected initiator-related condition.

Abstract: An apparatus 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 multi-path input-output driver configured to schedule input-output operations for delivery to the storage system over the network. The multi-path input-output driver is further configured to measure latencies of respective ones of a plurality of paths from the host device to the storage system, to schedule particular ones of the input-output operations for delivery to the storage system over particular ones of the paths based at least in part on the measured latencies, and to control transmission of the particular input-output operations over the particular paths in accordance with the scheduling.

Abstract: Described are data movements techniques may include: receiving a plurality of write quotas for a plurality of physical media types; determining a first physical storage device of a first physical media type that is over utilized with respect to a write quota; selecting a first data portion of the first physical storage device for data movement; determining a target device that is not over utilized with respect to a write quota; determining an expected total write I/O workload of the target device after hypothetically moving the first data portion thereto; determining whether the expected total write I/O workload exceeds a write quota of the target device; and responsive to determining the total write I/O workload does not exceed the write quota for the target device, moving the first data portion to the target storage device.

Abstract: Techniques for processing I/O operations may include: detecting, at a host, a sequence of I/O operations to be sent from the host to a data storage system, wherein each of the I/O operations of the sequence specifies a target address included in a first logical address subrange of a first logical device; sending, from the host, the sequence of I/O operations to a same target port of the data storage system, wherein each of the I/O operations of the sequence includes an indicator denoting whether resources used by the same target port in connection with processing said each I/O operation are to be released subsequent to completing processing of said each I/O operation; receiving the sequence of I/O operations at the same target port of the data storage system; and processing the sequence of I/O operations.