Abstract: A technique for performing data deduplication operates at sub-block granularity by searching a deduplication database for a match between a candidate sub-block of a candidate block and a target sub-block of a previously-stored target block. When a match is found, the technique identifies a duplicate range shared between the candidate block and the target block and effects persistent storage of the duplicate range by configuring mapping metadata of the candidate block so that it points to the duplicate range in the target block.

Abstract: Techniques for providing an adaptive approach to prefetching data for sequential read streams in a storage system. The techniques can include performing prefetch operations for a sequential read stream in accordance with a prefetch distance and a prefetch size, counting or otherwise keeping track of occurrences of failure scenarios in the prefetch operations while servicing the sequential read stream, and modifying or adjusting one of the prefetch distance and the prefetch size based on the occurrences of the respective failure scenarios. In this way, host input/output (IO) latency can be reduced, and IO bandwidth can be increased, in the servicing of sequential read streams by the storage system.

Abstract: A technique for achieving data mobility between storage systems having different block sizes includes identifying a baseline size that is common to the block sizes of the storage systems. The technique further includes generating fingerprints of blocks based on extents having the common baseline size. Fingerprint-based data mobility is then achieved by comparing extent-based fingerprints, or combinations thereof, across different storage systems to identify matching data.

Abstract: A technique for performing deduplication calculates a first fingerprint of a candidate block using a first function and a second fingerprint of the candidate block using a second function. The technique uses the first fingerprint to identify a target block, which is a potential match to the candidate block in the storage system. The technique then attempts to verify the potential match by accessing a fingerprint of the target block, which was previously calculated using the second function. The technique compares the fingerprint of the target block to the second fingerprint of the candidate block. A match between the two fingerprints confirms that the data of the candidate block matches the data of the target block. Storage of the candidate block can then be effectuated by reference to the target block.

Abstract: Techniques are provided for reporting space savings due to pattern matching in storage systems. For example, in one embodiment, an exemplary method comprises, when a given allocation unit in a storage system matches one or more predefined patterns, (i) setting a corresponding pattern flag for the given allocation unit, and (ii) incrementing at least one pattern counter; generating at least one snapshot of at least a portion of a file comprising the given allocation unit; and determining a range of data reduction attributed to pattern matching based on said at least one pattern counter, wherein one extreme of said range of data reduction attributed to pattern matching excludes said one or more predefined patterns in said at least one snapshot.

Abstract: A method is used in analyzing a storage system using a machine learning system. Data gathered from information associated with operations performed in a storage system is analyzed. The storage system is comprised of a plurality of components. A bitmap image is created based on the gathered data, where at least one of the plurality of components is represented in the bitmap image. The machine learning system is trained using the bitmap image, where the bitmap image is organized to depict the plurality of components of the storage system.

Abstract: A technique for scheduling tasks in a storage system includes predicting excess capacity of processing resources over a known interval of time and determining a quantity of credit based on the predicted capacity. The technique further includes holding back a requested increase in the priority of one or more speed-noncritical tasks by consuming a portion of the credit and thus allowing one or more speed-critical tasks to run with undiminished access to the processing resources.

Abstract: A method, computer program product, and computing system for allocating a first number of tokens from a plurality of tokens for processing read IO requests from a read IO queue, thus defining a number of allocated read tokens. A second number of tokens may be allocated from the plurality of tokens for processing write IO requests from a write IO queue, thus defining a number of allocated write tokens. It may be determined that the processing of the write IO requests is throttled. In response to determining that the processing of the write IO requests from the write IO queue is throttled, a maximum allowable number of write tokens may be defined. Additional tokens may be allocated for processing the read IO requests from the read IO queue based upon, at least in part, the maximum allowable number of write tokens and the number of allocated write tokens.

Abstract: Techniques for managing storage may comprise: receiving a request for a first amount of free capacity, wherein the request includes a first priority denoting a purpose for which the first amount of free capacity is requested; determining whether a current utilization of storage exceeds a first threshold associated with the first priority; responsive to determining the current utilization of storage is less than the first threshold associated with the first priority, performing first processing including: determining whether there is a sufficient amount of existing free capacity to grant the first amount; and responsive to determining there is a sufficient amount of existing free capacity to grant the first amount, granting the first amount of free capacity; and responsive to determining the current utilization of storage is not less than the first threshold associated with the first priority, rejecting the request and not granting the first amount of free capacity.

Abstract: A technique of obtaining attributes associated with data includes providing an attribute-only read request directed to a specified data element, accessing metadata structures that store one or more attributes associated with the specified data element, and returning the attribute (or attributes) but not the data itself in response to the request.

Abstract: A technique of protecting data from ransomware attacks identifies a set of blocks written to a data object between first and second points in time, determines a set of attributes of the set of blocks, and, in response to the set of attributes indicating a likelihood of a ransomware attack, secures a state of the data object as of the first point in time.

Abstract: Techniques for providing an adaptive approach to prefetching data for sequential read streams in a storage system. The techniques can include performing prefetch operations for a sequential read stream in accordance with a prefetch distance and a prefetch size, counting or otherwise keeping track of occurrences of failure scenarios in the prefetch operations while servicing the sequential read stream, and modifying or adjusting one of the prefetch distance and the prefetch size based on the occurrences of the respective failure scenarios. In this way, host input/output (IO) latency can be reduced, and IO bandwidth can be increased, in the servicing of sequential read streams by the storage system.

Abstract: A data storage system can include a deduplicated data cache used to store unique deduplicated data portions. Data portions can be promoted to the deduplicated data cache in connection with servicing I/O operations. Servicing the I/O operation that reads data from, or writes data to, a logical address can include determining whether a data portion stored at the logical address meets criteria for promoting the data portion to a deduplicated data cache. The criteria can include a condition that the data portion is a duplicate of content stored at multiple logical addresses, and can include a condition that the data portion has a reference count that is at least a minimum threshold where the reference count denotes a number of logical addresses at which the data portion is stored. Responsive to determining the data portion meets the criteria, the data portion can be stored in the deduplicated data cache.

Abstract: A technique of identifying hosts suspected of being sources of ransomware infection includes initiating a tracking interval in response to a data storage system detecting a suspected ransomware attack. During the tracking interval, write requests received by the data storage system are analyzed and ransomware attributes for those write requests are generated. The ransomware attributes of the write requests indicate risks of ransomware infection and are associated with hosts from which the respective write requests originate. A particular host is identified as a suspected source of ransomware infection based at least in part on the ransomware attributes associated with that host.

Abstract: A technique for managing a metadata transaction log consolidates multiple mapping pointer changes that affect a single metadata block in a single transaction entry. The technique creates a data structure that identifies the mapping pointers in the metadata block that are changing, and stores the data structure in the transaction entry along with records that describe the individual mapping pointer changes.

Abstract: A method, computer program product, and computing system for processing memory page metadata received from a cache memory system within a data storage system to determine if the memory page metadata includes corruption due to a power failure event; if the memory page metadata includes post-acknowledgement data corruption, initiating a data recovery process to attempt to recover content associated with the post-acknowledgement data corruption; and if the memory page metadata includes pre-acknowledgement data corruption, reobtaining content associated with the pre-acknowledgement data corruption.

Abstract: A method is used for managing overlapping communications regarding downtiering and invalidating cached data among nodes in a storage system. The method includes identifying, by a node, data to downtier. The node adds the data to an in progress table, and sends a request for permission to downtier the data to a peer node. The node receives permission from the peer node to downtier the data. In response to the permission to downtier the data, the node checks the in progress table for the data and takes an action based on a result of checking the in progress table.

Abstract: A technique for managing a datapath of a data storage system includes receiving a request to access target data and creating a transaction that includes multiple datapath elements in a cache, where the datapath elements are used for accessing the target data. In response to detecting that one of the datapath elements is invalid, the technique further includes processing the transaction in a rescue mode. The rescue mode attempts to replace each invalid datapath element of the transaction with a valid version thereof obtained from elsewhere in the data storage system. The technique further includes committing the transaction as processed in the rescue mode.

Abstract: A technique for managing a mapping structure in a data storage system includes identifying levels in the mapping structure of pages to be removed and estimating the workload required for removing the pages based at least in part on the identified levels. The technique further includes initiating processing of the pages based at least in part on the estimated workload.

Abstract: A method is used for managing overlapping communications regarding downtiering and invalidating cached data among nodes in a storage system. The method includes identifying, by a node, data to downtier. The node adds the data to an in progress table, and sends a request for permission to downtier the data to a peer node. The node receives permission from the peer node to downtier the data. In response to the permission to downtier the data, the node checks the in progress table for the data and takes an action based on a result of checking the in progress table.