Abstract: A method is used in ensuring data integrity in data storage. A set of physical pages that include data for a virtual page is identified on a storage device. A set of reconstructed pages is generated from other storage devices, and each reconstructed page corresponds to a page in the set of physical pages. One or more pages from the set of physical pages and the set of reconstructed pages with data yielding a checksum that matches a checksum for the virtual page is identified, and data corresponding to the virtual page from the identified one or more pages is obtained.

Abstract: A method of managing storage resources is provided. The method includes (a) storing data in an array of storage extents on respective storage drives of a plurality of storage drives, the array of storage extents having a first level of redundancy; and (b) in accordance with a storage management policy, adjusting the array of storage extents to have a second level of redundancy by changing the array of storage extents from having a first number of storage extents on respective storage drives to having a second number of storage extents on respective storage drives, the second level of redundancy providing a different tolerance for failure than the first level of redundancy. An apparatus, system, and computer program product for performing a similar method are also provided.

Abstract: A method, computer program product, and computer system for identifying, by a computing device, a pattern in a super block of a logger tier. it may be determined that the pattern in the super block of the logger tier is a known pattern, wherein the known pattern indicates invalid data in the logger tier. The logger tier may be booted up by storing an unknown pattern in the super block into the logger tier, wherein the unknown pattern indicates valid data in the logger tier.

Abstract: A method, computer program product, and computing system for processing higher-level metadata portions to identify each occurrence of a pointer to a lower-level metadata portion; and generating a pointer record within a memory device that memorializes each occurrence of a pointer to a lower-level metadata portion and identifies a specific lower-level metadata portion to which the pointer is pointing, thus resulting in a plurality of pointer records.

Abstract: A method, computer program product, and computing system for maintaining a first cursor pointer for a memory system, wherein the first cursor pointer concerns a first search criteria and identifies an initial first cursor starting location; receiving a first search request for the memory system that satisfies the first search criteria; executing the first search request within an initial first search window starting at the initial first cursor starting location; and updating the first cursor pointer to identify an updated first cursor starting location based, at least in part, upon the initial first search window.

Abstract: A method, computer program product, and computer system for identifying a bit for an allocation unit. It may be determined if data has been modified on the allocation unit while degraded. A rebuild of the allocation unit may be executed when the bit is a first value. The rebuild of the allocation unit may be skipped when the bit is a second value.

Abstract: A method, computer program product, and computer system for determining, by a computing device, a weight of an indirect block page. The weight of the indirect block page may be compared to a threshold. it may be determined that the weight of the indirect block page is greater than the threshold. A copy of the indirect block page may be created as a backup page based upon, at least in part, determining that the weight of the indirect block page is greater than the threshold.

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, computer program product, and computing system for processing higher-level metadata portions to identify each occurrence of a pointer to a lower-level metadata portion; and generating a pointer record within a memory device that memorializes each occurrence of a pointer to a lower-level metadata portion and identifies a specific lower-level metadata portion to which the pointer is pointing, thus resulting in a plurality of pointer records.

Abstract: A method, computer program product, and computer system for determining, by a computing device, a weight of an indirect block page. The weight of the indirect block page may be compared to a threshold. It may be determined that the weight of the indirect block page is greater than the threshold. A copy of the indirect block page may be created as a backup page based upon, at least in part, determining that the weight of the indirect block page is greater than the threshold.

Abstract: Coordinating a reclaiming of data storage space among processing nodes of a data storage system includes, by a first node in response to an event, performing local cleanup of first-node mapping data and issuing a request message to a second node, the request message identifying the data storage space to be reclaimed. The event may be a notification from a RAID component rebuilding a RAID volume. In response to the request message, the second node performs local cleanup of second-node mapping data and issues a completion message to the first node indicating that the second node has completed its part of the reclaiming of the data storage space. The first node responds to the completion message by marking the data storage space as being reclaimed and signaling to a source of the event that the data storage space is available for new use.

Abstract: Host data stored in one or more source physical extents of non-volatile data storage is identified as valid and determined to be infrequently written by host I/O requests, and is therefore compressed to generate a highly compressed version of the valid host data. The highly compressed version is then stored into at least one target physical extent. The valid host data may be initially compressed before it is stored in the source physical extent(s), and may be re-compressed to generate the highly compressed version. If the valid host data is also infrequently read, it may be recompressed using larger blocks of host data than were used to perform the initial compression. The performance tier of the target physical extent may be different from (e.g. lower than) the performance tier of the source physical extent. The technology may be embodied in a background process such as a garbage collector.

Abstract: A data storage system in which data storage space for storing data storage metadata is selectively allocated from non-volatile data storage devices contained in a first storage enclosure. The first storage enclosure is directly connected to at least one storage processor of the data storage system, and the data storage system further includes at least one secondary storage enclosure that is indirectly connected to the storage processor. Data storage metadata is generated within the data storage system, and the data storage metadata generated within the data storage system is stored into the data storage space that was selectively allocated for storing data storage metadata from the non-volatile data storage devices contained in the first storage enclosure.

Abstract: A data storage system in which a transaction is generated that indicates at least one data block of a logical volume to be written to non-volatile data storage of a data, and in which the logical volume is accessible to multiple nodes in the data storage system. A system-wide lock is obtained for each data block indicated by the transaction. A new generation identifier is then created that is equal to a last transaction identifier that was created and stored during processing of a previously completed transaction. Each data block indicated by the transaction is stored into the non-volatile data storage of the data storage system together with the new generation identifier and the last transaction identifier is updated before each system-wide lock on each data block indicated by the transaction is released.

Abstract: A data storage system performs updating of a set of global counters stored in persistent storage accessible to a plurality of processing nodes of a data storage system, the global counters storing respective global count values describing associated units of data storage shared by the processing nodes for performing data storage operations. The updating includes, by each processing node, using a respective set of in-memory delta counters storing respective delta count values to track changes to respective global count values due to data storage operations performed by the processing node with respect to the units of data storage. A summarization process is regularly executed to merge the delta count values of the delta counters of all processing nodes into the respective global counters.

Abstract: A data storage system in which physical extents of non-volatile data storage are provisioned from non-volatile data storage devices of disparate types for purposes of data mirroring. Data indicated by at least one write operation is mirrored onto the physical extents of non-volatile data storage provisioned from the non-volatile data storage devices of disparate types. A change in performance requirements for the data may cause a new physical extent to be provisioned from another type of non-volatile data storage device, and then used to replace one of the originally provisioned physical extents, such that data indicated by subsequently received write operations is mirrored onto the newly provisioned physical extent and those of the originally provisioned physical extents that were not replaced by the newly provisioned physical extent.

Abstract: A method of responding to failures in a tiered storage system is provided. The method includes (a) rebuilding a set of failed storage extents belonging to a first storage tier; (b) receiving a notification that a particular storage extent has failed while rebuilding the set of failed storage extents belonging to the first tier; and (c) upon determining that the particular storage extent belongs to a second storage tier that has a higher priority than does the first storage tier: (1) pausing rebuilding the set of failed storage extents belonging to the first storage tier, (2) rebuilding the particular storage extent, and (3) resuming rebuilding the set of failed storage extents belonging to the first storage tier after rebuilding the particular storage extent. An apparatus, system, and computer program product for performing a similar method are also provided.

Abstract: A method, computer program product, and computer system for receiving, by a computing device, new data to write to a leaf. At least two timestamps of the leaf may be examined. It may be determined whether a time interval between the at least two timestamps of the leaf is greater than an age threshold. The new data may be written to a first tier storage device when the time interval between the at least two timestamps of the leaf is less than the age threshold; The new data may be written to a second tier storage device when the time interval between the at least two timestamps of the leaf is greater than the age threshold.

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: A technique is directed to storing data on a plurality of storage devices of a data storage array. The technique involves, on each storage device of the plurality of storage devices, providing large disk extents and small disk extents for allocation to RAID extents. The technique further involves forming, from the large disk extents, a user-data RAID extent to store user data for the data storage array. The technique further involves forming, from the small disk extents, an internal-metadata RAID extent to store internal metadata for the data storage array. In some arrangements, spare space is reserved on one or more storage devices between large and small disk extents.