Abstract: A method comprises maintaining stripe metadata corresponding to stripes of data stored on a plurality of storage devices. The stripe metadata comprises a first timestamp, a second timestamp and a read count for each stripe. The method comprises obtaining a read request associated with a given stripe and having an associated timestamp and determining whether or not a time period for the given stripe has been exceeded. The method comprises updating the stripe metadata corresponding to the given stripe based at least in part on the determination and the associated timestamp and determining a read access frequency of the given stripe based at least in part on the read count, the first timestamp and the second timestamp of the updated stripe metadata. The method comprises performing at least one of a defragmentation process and a rebuild process based at least in part on the determined read access frequency.

Abstract: An apparatus comprises a processing device. The processing device is configured to persistently store metadata pages on a plurality of storage devices. The metadata pages are organized into buckets. The processing device is configured to access a given metadata page based at least in part on a bucket identifier where the given metadata page corresponds to a given logical volume. The bucket identifier comprises a first portion comprising an indication of a given bucket range that corresponds to the given logical volume and a second portion comprising an indication of an offset into the given bucket range that corresponds to a grouping of buckets that correspond to the given logical volume. The grouping of buckets corresponds to the given logical volume. The bucket identifier further comprises a third portion comprising an indication of an offset into the grouping of buckets that corresponds to the bucket comprising the given metadata page.

Abstract: An apparatus comprises a processing device. The processing device is configured to persistently store metadata pages on a plurality of storage devices. The metadata pages are organized into buckets. The processing device is configured to access a given metadata page based at least in part on a bucket identifier where the given metadata page corresponds to a given logical volume. The bucket identifier comprises a first portion comprising an indication of a given bucket range that corresponds to the given logical volume and a second portion comprising an indication of an offset into the given bucket range that corresponds to a grouping of buckets that correspond to the given logical volume. The grouping of buckets corresponds to the given logical volume. The bucket identifier further comprises a third portion comprising an indication of an offset into the grouping of buckets that corresponds to the bucket comprising the given metadata page.

Abstract: A method, computer program product, and computing system for during a high IOPs period, receiving content to be written to a storage system; storing the content to a specific location within a storage device associated with the storage system; updating a temporary map to include an entry that defines the specific location of the content; and during a subsequent period, binding the content with respect to the storage device.

Abstract: Techniques for estimating performance metrics of standalone or clustered storage systems. The techniques include receiving a request from a storage client for an estimated capacity or capability of a storage system to handle a specified workload pattern within a specified periodicity interval, in which the estimated capacity or capability of the storage system is represented by a headroom metric. The techniques further include, in response to the request from the storage client, obtaining a value of the headroom metric for the specified periodicity interval using a performance model characterized by at least a peak load reserve (PLR) metric and a long-term load reserve (LLR) metric, in which the obtained value of the headroom metric corresponds to the minimum of respective values of at least the PLR metric and the LLR metric. The techniques further include upgrading, scaling-up, and/or scaling-out the storage system based on the value of the headroom metric.

Abstract: A storage system in one embodiment comprises storage nodes, an address space, address mapping sub-journals and write cache data sub-journals. Each address mapping sub-journal corresponds to a slice of the address space, is under control of one of the storage nodes and comprises update information corresponding to updates to an address mapping data structure. Each write cache data sub journal is under control of the one of the storage nodes and comprises data pages to be later destaged to the address space. A given storage node is configured to store write cache metadata in a given address mapping sub journal that is under control of the given storage node. The write cache metadata corresponds to a given data page stored in a given write cache data sub-journal that is also under control of the given storage node.

Abstract: In a method of flushing cached data in a data storage system, instances of a working-set structure (WSS) are used over a succession of operating periods to organize cached data for storing to the persistent storage. In each operating period, leaf structures of the WSS are associated with respective address ranges of a specified size. Between operating periods, a structure-tuning operation is performed to adjust the specified size and thereby dynamically adjust a PD-to-leaf ratio of the WSS, including (1) comparing a last-period PD-to-leaf ratio to a predetermined ratio range, (2) when the ratio is below the predetermined ratio range, increasing the specified size for use in a next operating period, and (3) when ratio is above the predetermined ratio range, then decreasing the specified size for use in the next operating period.

Abstract: A method, computer program product, and computer system for acquiring, by a first node, local locks of the first node associated with a metadata log transaction, wherein the first node acquires the local locks of the first node prior to sending a commit message to a second node. The second node may acquire local locks of the second node associated with the metadata log transaction, wherein the second node acquires the local locks of the second node based upon, at least in part, receiving the commit message from the first node.

Abstract: A method, computer program product, and computer system for creating, by a computing device, a child leaf of a snapshot associated with a parent leaf of a volume. At least one entry associated with one of the parent leaf and the child leaf may be added to a delta log. Only delta changes are written to the child leaf. One of a first destaging technique and a second destaging technique may be used for the child leaf.

Abstract: A method, computer program product, and computing system for defining a queue. The queue may be based on a linked list and may be a first-in, first-out (FIFO) queue that may be configured to be use used with multiple producers and a single consumer. The queue may include a plurality of queue elements. A tail element and a head element may be defined from the plurality of elements within the queue. The tail element may point to a last element of the plurality of elements and the head element may point to a first element of a plurality of elements. An element may be dequeued from the tail element, which may include determining if the tail element is in a null state. An element may be enqueued to the head element, which may include adding a new element to the queue.

Abstract: A method, computer program product, and computing system for receiving a flush request for a metadata page stored in a storage array of a multi-node storage system. The flush request may be queued on a flush request lock queue on at least one node of the multi-node storage system. One or more flush requests may be processed, via multiple nodes of the multi-node storage system, on the metadata page based upon, at least in part, the flush request lock queue.

Abstract: A method, computer program product, and computing system for assigning a plurality of unique sequential identifiers to a plurality of tablets in a cache memory system. One or more metadata deltas associated with a metadata page stored in a storage array may be written to the plurality of tablets in the cache memory system. Each metadata delta stored in at least one tablet of the plurality of tablets may be written to the metadata page stored in the storage array, thus defining one or more destage tablets. A largest unique sequential identifier from the plurality of unique sequential identifiers assigned to the one or more destage tablets, may be written to the storage array, thus defining a current tablet identifier for the metadata page.

Abstract: A method, computer program product, and computer system for controlling, by a computing device, access to a non-volatile memory using a non-volatile lock as a reader of the non-volatile memory. Metadata (MD) non-volatile memory commits may be throttled until capacity of the non-volatile memory is at a threshold capacity.

Abstract: A method, computer program product, and computer system for permitting, by a computing device, entering of a barrier object of a plurality of barrier objects with a first set of one or more Application Programming Interfaces (APIs) only when the barrier object is not set. The first set of the one or more APIs on the barrier object may wait until the barrier object is reset. A second set of the one or more APIs may set the barrier object. Waiting may occur until there are no longer any flows in the barrier object.

Abstract: An apparatus comprises at least one processing device that includes a processor coupled to a memory. The processing device is configured to associate a first storage node with at least a second storage node in a plurality of storage nodes of a distributed storage system, each such storage node comprising a plurality of storage devices, to establish a storage devices group comprising specified ones of the storage devices of the first and second storage nodes, to detect an issue with a first communication channel to the first storage node, and responsive to the detected issue, to communicate with the first storage node via the second storage node, utilizing an alternative communication channel involving one or more storage devices of the storage devices group. The storage devices group may comprise a designated subset of storage devices within a common disk array enclosure (DAE) shared by the first and second storage nodes.

Abstract: A method of performing write operations that have been received by a data storage apparatus is provided. The method includes (a) storing page descriptors for received write operations within temporary storage, each page descriptor indicating respective data to be written; (b) upon storing each page descriptor, organizing that page descriptor into a shared working-set structure; and (c) operating a plurality of flushers to persist the data indicated by respective page descriptors to long-term persistent storage based on organization of the page descriptors in the shared working-set structure, each flusher accessing page descriptors via the shared working-set structure. An apparatus, system, and computer program product for performing a similar method are also provided.

Abstract: Managing pool memory in a data storage system includes maintaining free lists for corresponding object sizes. For a memory-consuming request (e.g., host write) an allocation operation is performed and the request data is stored. The allocation operation includes (1) selecting a memory object at least as large as the request size and removing all pages of the selected memory object from the corresponding free list, and (2) selecting pages of the selected memory object to store the request data and marking the selected pages as non-free, and leaving any leftover pages as free pages. For a memory-freeing request (e.g., destaging), a deallocation operation is performed that includes (1) marking the request pages free, and (2) based on neighboring pages being free, merging the request pages and neighboring pages into a corresponding memory object and adding the merged pages to the corresponding free list.

Abstract: A technique for managing messaging between storage nodes of a storage system includes a first storage node delaying the sending of non-latency-critical messages to a second storage node until the first storage node has a latency-critical message to be sent. The technique further includes combining the non-latency-critical messages with the latency-critical message to form a single, aggregated message, and sending the aggregated message to the second storage node.

Abstract: At least one processing device comprises a processor and a memory coupled to the processor. The at least one processing device is configured to establish one or more groups of synchronization objects in a storage system based at least in part on object type, and for each of the one or more groups, to insert entries into a corresponding object type queue for respective objects of the group, to execute a monitor thread for the group, the monitor thread being configured to scan the entries of the corresponding object type queue, and responsive to at least one of the scanned entries meeting one or more designated conditions, to take at least one automated action for its associated object. The synchronization objects illustratively comprise respective locks, or other objects. The at least one processing device illustratively comprises at least a subset of a plurality of processing cores of the storage system.

Abstract: Techniques are used for improving performance of a storage system. The techniques may be used to provide, among other things, a set of counters for an object. Each counter corresponds to a unique processor in a multi-processor storage system. The state of a gate governing the object is determined. If the state of the gate is open, the counter corresponding to the first processor is incremented. The state of the gate for the object is re-determined. If the state of the gate remains open, the object is read and the counter corresponding to the first storage processor is decremented.