Abstract: In one aspect, performance optimization for data persistency in asynchronous replication setups includes creating at a source site of a data replication system, a snapshot (snapshot N) of input/output (IO) requests as part of a replication cycle, computing a delta of snapshot N and a previously created snapshot (snapshot N?1), and transmitting the delta to a target site of the data replication storage system. An aspect further includes storing, at the target site, snapshot N?1 during transmission of the delta, and caching the delta to a non-persistent storage device. Upon determining an occurrence of a loss event at the target site, a further aspect includes transmitting, by the target site, a request to retransmit the delta, retransmitting, by the source site, the delta to the target site, caching the delta to the non-persistent storage device until successful transmission of the delta, and committing the transmitted delta to permanent storage.

Abstract: A storage system in one embodiment comprises a plurality of storage devices and a storage controller. The storage controller is configured to generate a plurality of snapshots of a storage volume of the storage system at respective different points in time, to monitor a differential between a given one of the snapshots and the storage volume, and to generate an alert indicative of at least a potential ransomware attack on the storage system based at least in part on the monitored differential satisfying one or more specified conditions. The one or more specified conditions illustratively comprise a specified minimum amount of change in the storage volume relative to the given snapshot of the storage volume. Compressibility of the storage volume is also taken into account in generating the alert in some embodiments. The storage controller illustratively initiates restoration of the storage volume utilizing a selected snapshot responsive to confirmation of an actual attack.

Abstract: An apparatus in one embodiment comprises at least one processing device comprising a processor coupled to a memory. The processing device is configured to detect an error relating to storage of a given data page in a first storage system, and to send a message to at least one additional storage system, the message containing a hash handle of the given data page with the hash handle having a length that is shorter than that of a corresponding hash digest of the given data page. The processing device is further configured to receive from the additional storage system responsive to the message a recovery data page identified by the additional storage system as having the same hash handle as the given data page. Separate instances of the message containing the hash handle of the given data page may be sent to each of a plurality of additional storage systems.

Abstract: Example embodiments of the present invention relate to methods, systems, and computer program products for determining replicas for removal from a plurality of replicas as defined in a data retention policy. The method includes performing asynchronous replication from a source to a target according to time-based replication cycles. A retention policy then may be identified defining a number of asynchronous replication replicas to retain and a plurality of associated periods which then may be retained according to the policy.

Abstract: A storage system in one embodiment comprises a plurality of storage devices and an associated storage controller. The storage controller is configured to identify a dataset to be scanned to generate a capacity release estimate for prospective deletion of that dataset, to designate a content-based signature prefix to be utilized in the scan, and to scan logical address mapping information for the dataset to identify one or more pages of the dataset that have the designated content-based signature prefix. The scanning further comprises, for each such identified page, determining a reference count of the page, and responsive to the reference count of the page having a particular value, determining a compressibility measure for the page. The storage controller generates the capacity release estimate for prospective deletion of the dataset based at least in part on the one or more page compressibility measures determined as part of the scan.

Abstract: An apparatus in one embodiment comprises at least one processing device comprising a processor coupled to a memory, with the processing device being configured to obtain content-based signatures for respective data pages of at least one write operation, to send the content-based signatures to a content addressable storage (CAS) system, and to receive from the CAS system information indicating for each of the content-based signatures whether or not the corresponding data page is present in the CAS system. Responsive to the information received from the CAS system indicating that one or more of the corresponding data pages are not present in the CAS system, the processing device sends the one or more corresponding data pages to the CAS system. The processing device illustratively comprises a host device coupled to the CAS system over a network.

Abstract: A method, computer program product, and computer system for invalidating, by a target, all data in a first volume. A source may scan a hash to address table for a second volume to be migrated to the first volume. Data in the second volume may be migrated to be stored in the first volume by pushing information from the hash to address table to the target.

Abstract: An apparatus includes at least one processing device comprising a processor coupled to a memory, with the processing device being configured to maintain throughput statistics for at least portions of one or more asynchronous replication cycles of a replication process carried out between a first storage system and a second storage system, and to control a transition of the replication process from an asynchronous replication mode to a synchronous replication mode based at least in part on the maintained throughput statistics. The throughput statistics are illustratively updated in conjunction with each of a plurality of detected suspensions of the synchronous replication mode, and the asynchronous replication mode is reinitiated responsive to each of the detected suspensions of the synchronous replication mode. Other embodiments include methods and computer program products.

Abstract: A method, computer program product, and computer system for receiving, by a target sent from a source, a first hash signature associated with a page of data. It may be determined that the first hash signature exists on the target. The target may receive a second hash signature sent from the source associated with the page of data. A third hash signature may be generated at the target. It may be determined that the second hash signature matches the third hash signature indicating the page of data exists on the target. A data-less write command may be executed using the page of data existing on the target to deduplicate the page of data existing on the target.

Abstract: An apparatus in one embodiment comprises at least one processing device comprising a processor coupled to a memory, with the processing device being configured to obtain content-based signatures for respective data pages of at least one write operation, to send the content-based signatures to a content addressable storage (CAS) system, and to receive from the CAS system information indicating for each of the content-based signatures whether or not the corresponding data page is present in the CAS system. Responsive to the information received from the CAS system indicating that one or more of the corresponding data pages are not present in the CAS system, the processing device sends the one or more corresponding data pages to the CAS system. The processing device illustratively comprises a host device coupled to the CAS system over a network.

Abstract: An apparatus in one embodiment comprises at least one processing device comprising a processor coupled to a memory. The processing device is configured to identify a dataset to be scanned to generate a deduplication estimate for that dataset, to designate a subset inclusion characteristic to be utilized in the scan, and for each of a plurality of pages of the dataset, to scan the page, where scanning the page includes computing a polynomial-based signature for the page, determining whether or not the polynomial-based signature satisfies the designated subset inclusion characteristic, and responsive to the polynomial-based signature satisfying the designated subset inclusion characteristic, computing a content-based signature for the page and updating a corresponding entry of a deduplication estimate table for the dataset based at least in part on the content-based signature.

Abstract: An apparatus in one embodiment comprises at least one processing device comprising a processor coupled to a memory. The processing device is configured to identify a dataset to be scanned to generate a deduplication estimate for that dataset, to designate a content-based signature prefix to be utilized in the scan, and for each of a plurality of pages of the dataset, to scan the page, where scanning the page includes computing a content-based signature for the page, comparing an initial portion of the content-based signature to the designated content-based signature prefix, and responsive to a match between the initial portion and the designated content-based signature prefix, updating a corresponding entry of a deduplication estimate table for the dataset. The processing device generates the deduplication estimate for the dataset based at least in part on contents of the deduplication estimate table.

Abstract: A storage system in one embodiment comprises a plurality of storage devices and a storage controller. The storage system is configured to implement a loopback replication process in which one or more source storage objects are replicated to one or more corresponding target storage objects within the storage system. The storage system is further configured to divide a storage space provided by at least portions of the storage devices of the storage system into slices, to subdivide the slices into source slices and target slices, and to replicate a source storage object associated with at least one of the source slices to a target storage object associated with at least one of the target slices. The source storage object may be associated with at least one of the source slices by, for example, storing the source storage object across portions of the storage devices in designated ones of the source slices.

Abstract: A first storage system in one illustrative embodiment is configured to participate in a replication process with a second storage system. Each of a plurality of storage nodes of the first storage system comprises a plurality of storage devices and a set of processing modules configured to communicate with corresponding sets of processing modules on other ones of the storage nodes. In conjunction with the replication process, a first one of the processing modules is configured to generate a request message for transmission to a second one of the processing modules requesting that the second processing module transfer designated replication data to the second storage system. The request message comprises a unique message identifier that the second processing module incorporates into a subsequent response message transmitted back to the first processing module to indicate a result of the requested transfer of the designated replication data to the second storage system.

Abstract: An apparatus in one embodiment comprises at least one processing device comprising a processor coupled to a memory. The processing device is configured to detect an error relating to storage of a given data page in a first storage system, and to send a message to at least one additional storage system, the message containing a hash digest of the given data page. The processing device is further configured to receive from the additional storage system responsive to the message a recovery data page identified by the additional storage system as having the same hash digest as the given data page. The recovery data page received from the additional storage system is verified by computing a hash digest of the recovery data page and comparing the computed hash digest to the hash digest of the given data page. Separate instances of the message containing the hash digest of the given data page may be sent to each of a plurality of additional storage systems.

Abstract: A first storage system sends a clock synchronization message to a second storage system. The first storage system records a first value of a local time in the first storage system in conjunction with sending the clock synchronization message, and records a second value of the local time in the first storage system in conjunction with receipt of a response to the clock synchronization message from the second storage system. The response comprises a value of a local time in the second storage system. The first storage system computes an estimate of a difference between the local times using the recorded first and second values of the local time in the first storage system and the received value of the local time in the second storage system, and synchronizes the local time in the first storage system with the local time in the second storage using the computed estimate.

Abstract: A method, computer program product, and computer system for preparing, by a computing device, for migration of data from a source to a target. Hash values of the data may be sorted at the source. The data may be migrated from the source to the target according to how the data was sorted at the source.

Abstract: A processing device identifies a first snapshot to be split from a first snapshot group, generates a second snapshot of the first snapshot, continues write operations to the first snapshot, copies the second snapshot to a storage volume of a second snapshot group, and computes a differential between the first and second snapshots. Responsive to the differential between the first and second snapshots being above a specified threshold, an additional snapshot of the first snapshot is generated, a differential is computed between the additional snapshot and a previous snapshot of the first snapshot, and if necessary the generating of an additional snapshot and the computing of a differential are repeated one or more additional times, until the differential is at or below the specified threshold. The processing device updates the storage volume based at least in part on one or more of the computed differentials.

Abstract: An apparatus obtains a set of content-based signatures for respective data pages of at least a portion of at least one storage volume replicated from a source storage system to a target storage system, issues a write for the set of content-based signatures to the target storage system, and reads from a designated location in the target storage system information indicating for each of the content-based signatures whether or not the corresponding data page is present in the target storage system. For one or more data pages not present in the target storage system, the apparatus writes the one or more data pages to respective logical addresses of the replicated storage volume in the target storage system. The issuing of a write, the reading from the designated location, and the writing of the one or more data pages are illustratively performed utilizing respective commands of a standard storage command protocol.

Abstract: A storage system in one embodiment comprises a plurality of storage devices and a storage controller. The storage system is configured to participate as a target storage system in a replication process with a source storage system. In conjunction with the replication process, the target storage system is configured to receive from the source storage system replication data for at least one storage volume subject to replication from the source storage system to the target storage system, to generate a first snapshot for the storage volume, to monitor additional replication data received from the source storage system for the storage volume after generation of the first snapshot, and responsive to the monitored additional replication data satisfying one or more specified conditions, to perform at least one of the following operations: (i) generating a subsequent snapshot for the storage volume; and (ii) marking the first snapshot with a priority indicator.