Abstract: A method, computer program product, and computer system for obtaining, by a computing device, one or more pages from a log to complete a write transaction. Parity of a line in a multi-line physical layer block may be calculated. The one or more pages may be written to the line in the multi-line physical layer block. The parity to the line may be written in the multi-line physical layer block. A bitmap associated with the physical layer block may be updated based upon, at least in part, writing the one or more pages and the parity to the line in the multi-line physical layer block.

Abstract: A method is used in host-based caching. A host receives a request for data, and identifies a host in a plurality of hosts that owns the data.

Abstract: A method is used in issuing alerts for storage volumes using machine learning. A machine learning system analyzes Input/Output (I/O) data of a storage volume in a data storage system. The machine learning system is trained with sample I/O data patterns associated with the storage volume. Based on the I/O data, the machine learning system identifies atypical behavior associated with I/O data patterns of the I/O data. The method then issues an alert.

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 compression estimate for that dataset, to designate a scan criterion 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 performing a computation on the page to obtain a page result, determining whether or not the page result satisfies the designated scan criterion, and responsive to the page result satisfying the designated scan criterion, updating a corresponding entry of a compression estimate table for the dataset. The processing device generates the compression estimate for the dataset based at least in part on contents of the compression estimate table.

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 at least first and second datasets to be scanned to generate a data reduction estimate for a prospective combination of the first and second datasets, to designate a scan criterion to be utilized in the scan of each of the datasets, and for each of a plurality of pages of each of the datasets, to scan the page, where scanning the page comprises performing a computation on the page to obtain a page result, determining whether or not the page result satisfies the designated scan criterion, and responsive to the page result satisfying the designated scan criterion, updating a corresponding entry of a data reduction estimate table for the dataset. The processing device merges contents of the data reduction estimate tables, and generates the data reduction estimate based at least in part on the merged contents.

Abstract: Techniques for processing data may include: receiving a data block stored in a data set, wherein a hash value is derived from the data block; determining, in accordance with selection criteria, whether the hash value is included in a subset; responsive to determining the hash value is included in the subset, performing processing that updates a table in accordance with the hash value and the data set, and determining, in accordance with the information in the table, whether to perform deduplication processing for the data block to determine whether the data block is a duplicate of another stored data block. The table may include an entry for the hash value. The entry may include information identifying data sets referencing the data block and, for each of the data sets, may specify a reference count denoting a number of times the data set references the data block.

Abstract: A storage system comprises a plurality of storage nodes each comprising one or more storage devices and a processor coupled to a memory. The storage system is configured to store data blocks across the storage devices of the storage nodes utilizing a redundant array of independent disks (RAID) arrangement. At least a given one of the storage nodes is configured to store a plurality of RAID metadata bitmaps in persistent storage of the storage node so as to be available for a recovery operation in the event of a detected failure, to identify a particular subset of the RAID metadata bitmaps to be updated in conjunction with an additional operation other than the recovery operation, and to temporarily store the identified subset of the RAID metadata bitmaps in the memory of the storage node in a manner determined based at least in part on an operation type of the additional operation.

Abstract: A method is used in issuing alerts for storage volumes using machine learning. A machine learning system analyzes Input/Output (I/O) data of a storage volume in a data storage system. The machine learning system is trained with sample I/O data patterns associated with the storage volume. Based on the I/O data, the machine learning system identifies atypical behavior associated with I/O data patterns of the I/O data. The method then issues an alert.

Abstract: A method is used in issuing alerts for storage volumes using machine learning. A machine learning system analyzes Input/Output (I/O) data of a storage volume in a data storage system. The machine learning system is trained with sample I/O data patterns associated with the storage volume. Based on the I/O data, the machine learning system identifies atypical behavior associated with I/O data patterns of the I/O data. The method then issues an alert.

Abstract: Techniques are provided for application tracing for inline performance analysis.

Abstract: A storage system in one embodiment comprises multiple storage nodes each comprising at least one storage device. Each of the storage nodes further comprises a set of processing modules configured to communicate over one or more networks with corresponding sets of processing modules on other ones of the storage nodes. The sets of processing modules of the storage nodes each comprise at least one control module. The storage system is configured to assign portions of a logical address space of the storage system to respective ones of the control modules, to receive a plurality of tracks of data records in a count-key-data format, and to store the tracks in respective ones of the portions of the logical address space assigned to respective ones of the control modules. Each of the tracks is stored in its entirety in the portion of the logical address space assigned to a corresponding one of the control modules.

Abstract: Host I/O requests directed to a logical storage volume are initially processed by accessing physical pages of non-volatile data storage having a default page size. An indication of an optimal page size for the logical storage volume is received, and the size of the physical pages of non-volatile data storage accessed to process host I/O requests directed to the logical storage volume is changed from the default page size to the optimal page size for the logical storage volume. The default page size is changed to the optimal page size for the logical storage volume by changing a size of physical pages of non-volatile data storage indicated by a mapping structure that maps logical addresses in an address space the logical storage volume to corresponding physical pages of non-volatile data storage from the default page size to the optimal page size for the logical storage volume.

Abstract: Rebalancing the workload of logical devices across multiple nodes may include dynamically modifying preferred paths for one or more logical devices in order to rebalance the I/O workload of the logical devices among the nodes of the data storage system. Determining whether to rebalance the I/O workload between the two nodes may be performed in accordance with one or more criteria. Processing may include monitoring the current workloads of both nodes over time and periodically evaluating, in accordance with the one or more criteria, whether the current workloads of the nodes are imbalanced. Responsive to determining, in accordance with the criteria, that rebalancing of workload between the nodes is needed, the rebalancing may be performed. A notification may be sent to the host regarding any path state changes made as a result of the workload rebalancing.

Abstract: Example embodiments of the present invention provide a method, a system, and a computer program product for managing tasks in a system. The method comprises running a first task on a system, wherein the first task has a first priority of execution time and the execution of which first task locks a resource on the system, and running a second task on the system, wherein the second task has a second priority of execution time earlier than the first priority of execution time of the first task and the execution of which second task requires the resource on the system locked by the first task. The system then may promote the first task having the later first priority of execution time to a new priority of execution time at least as early as the second priority of execution time of the second task and resume execution of the first task having the later first priority of execution time.

Abstract: A storage system in one embodiment comprises a plurality of storage devices and a storage controller. The storage system is configured by the storage controller to receive a plurality of data records in a count-key-data format, to separate count and key portions of the data records from remaining portions of the data records, to store the count and key portions of the data records in at least one designated page of a set of pages of a logical storage volume of the storage system, and to store the remaining portions of the data records in one or more other pages of the set of pages of the logical storage volume of the storage system. The designated page of the set of pages of the logical storage volume may comprise a first page of the set of pages, and the one or more other pages of the set of pages may comprise respective ones of a sequence of consecutive pages following the first page.

Abstract: In one aspect a data replication process in a storage system includes creating, at a first target site, an empty container in a storage system. The empty container matches a container at a source site in response to initiation of an asynchronous data replication process. An aspect also includes transmitting a command to a second target site to create a container at the second target site. The first target site performs the asynchronous data replication process, which includes scanning the data upon receipt from the source site for a first target replication cycle and transmitting the scanned data to the container at the second target site for a second target replication cycle.

Abstract: A first storage system in one illustrative embodiment is configured to participate in a replication process with a second storage system. The first storage system detects a replication failure condition or other condition requiring termination of a synchronous replication mode of the replication process, and responsive to the detected condition, captures a snapshot of source data that is subject to replication from the first storage system to the second storage system as part of the replication process. The first storage system terminates the synchronous replication mode of the replication process, initiates an asynchronous replication mode of the replication process, executes an asynchronous-to-synchronous transition cycle scan operation for the replication process utilizing the captured snapshot, and resumes the synchronous replication mode of the replication process responsive to successful completion of the asynchronous-to-synchronous transition cycle scan operation.

Abstract: In one aspect, performing dynamic balancing of input/output (IO) operations includes providing a first queue for a first storage unit and a second queue for a second storage unit. The queues are configured to receive IO requests directed to the storage units. An aspect also includes determining a quality of service (QoS) value assigned to each of the storage units, pulling entries from the queues at a rate that accords with the QoS value, executing IOs, and monitoring bandwidth of the IO operations. Upon determining the bandwidth is not in alignment with the QoS value for either of the first and second storage units, a further aspect includes modifying the rate in which entries are pulled from at least one of the queues, continuing the monitoring the bandwidth and the modifying the rate until the bandwidth aligns with the QoS value assigned to each of the storage units.

Abstract: Techniques for data migration may include: copying data of a source logical device of a source system to a target logical device of a target system; during said copying, receiving at the target system an I/O operation directed to a logical address of the target logical device and intercepting the I/O operation on the target system; determining, on the target system, to request from the source system a data page stored at the logical address; responsive to determining to request the data page stored, performing processing including: issuing a request to the source system for the data page stored at the logical address; and responsive to receiving said request, sending information from the source system to the target system, wherein the information includes the data page stored at the logical address and additional logical addresses of the source logical device at which the data page is stored.

Abstract: Techniques for providing a direct IO path to compressed data on storage media of a storage system. The techniques include triggering a transaction cache to perform a flush operation for updating mapping metadata for a storage object containing the compressed data. Having updated the mapping metadata for the storage object, the techniques further include issuing, by a copier module, an IO read request for the compressed data of the storage object to a namespace layer, which issues the IO read request to a mapping layer. The techniques further include forwarding the IO read request to a logical layer of the mapping layer, bypassing the transaction cache. The techniques further include reading, by the logical layer, the compressed data of the storage object from the storage media, and providing, via the mapping layer and the namespace layer, the compressed data to the copier module for transfer to a destination storage system.