Abstract: In a dual node system, each node can store metadata updates in a volatile memory metadata log. Metadata pages can be used to access data stored on a volume. A node designated as preferred or affined for a volume can be expected to receive I/Os directed to the volume. A preferred node for a volume can record, in its volatile memory metadata log, the metadata changes for the metadata pages used to access data stored on the volume. A non-preferred or non-affined node for the volume can infrequently receive I/Os directed to the volume. A non-preferred node for a volume can record, in its volatile memory metadata log, pointers or references to the metadata changes for the metadata pages used to access data stored on the volume, where the pointers or references map to persisted copies of the meta changes as stored in a persisted metadata log.

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: In at least one embodiment, processing can include: receiving a request for a transaction of MD (metadata) updates including a first MD update of a first MD update type of a first set and including a second MD update of a second MD update type of a second set; storing, in a first volatile MD log, the first MD update; storing, in a second volatile MD log, the second MD update; storing, in a first non-volatile MD log, the first MD update; and storing, in a second non-volatile MD log, the second MD update, wherein each MD update of the first volatile MD log and the first non-volatile MD log has a corresponding MD update type of the first set, and each MD update of the second volatile MD log and the second non-volatile MD log has a corresponding MD update type of the second set.

Abstract: In a dual node system, each node can store metadata updates in a volatile memory metadata log. Metadata pages can be used to access data stored on a volume. A node designated as preferred or affined for a volume can be expected to receive I/Os directed to the volume. A preferred node for a volume can record, in its volatile memory metadata log, the metadata changes for the metadata pages used to access data stored on the volume. A non-preferred or non-affined node for the volume can infrequently receive I/Os directed to the volume. A non-preferred node for a volume can record, in its volatile memory metadata log, pointers or references to the metadata changes for the metadata pages used to access data stored on the volume, where the pointers or references map to persisted copies of the meta changes as stored in a persisted metadata log.

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 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 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 receiving, at a node of a multi-node storage system, one or more updates to a reference count associated with a metadata block. One or more reference count deltas associated with the metadata block may be stored in a cache memory system of the node. An existing copy of the metadata block in a cache memory system of each other node of the multi-node storage system may be retained.

Abstract: A method, computer program product, and computing system for receiving, at a node of a multi-node storage system, one or more updates to a reference count associated with a metadata block. One or more reference count deltas associated with the metadata block may be stored in a cache memory system of the node. An existing copy of the metadata block in a cache memory system of each other node of the multi-node storage system may be retained.

Abstract: A mapper tree for a logical volume is provided by storing, in each leaf node of the mapper tree, pointers to pages of non-volatile storage that store host data written to corresponding pages within a segment of the logical address space of the logical volume that corresponds to the leaf node. In response to receiving an initial write operation directed to a segment of the logical address space of the logical volume for which no leaf node currently exists in the mapper tree, a representation of a new leaf node is added to a super leaf node in the mapper tree that efficiently stores representations of multiple leaf nodes.

Abstract: Techniques for handling journal space in a storage cluster with multiple delta log instances. The techniques include writing delta updates for a respective metadata type to an “active” set of data containers in a delta log instance and raw delta updates to a raw delta log, switching a designation of the “active” set of data containers from “active” to “de-staging” once one or more of the “active” set of data containers has been filled, writing a bookmark for the respective metadata type to the raw delta log and a bookmark list, determining that a de-staging operation has been completed for writing the delta updates from the “de-staging” set of data containers to a storage array, determining that the bookmark for the respective metadata type is the oldest bookmark in the list, and reclaiming space between a tail of the raw delta log and the bookmark written to the raw delta log.

Abstract: A mapper tree for a logical volume is provided by storing, in each leaf node of the mapper tree, pointers to pages of non-volatile storage that store host data written to corresponding pages within a segment of the logical address space of the logical volume that corresponds to the leaf node. In response to receiving an initial write operation directed to a segment of the logical address space of the logical volume for which no leaf node currently exists in the mapper tree, a representation of a new leaf node is added to a super leaf node in the mapper tree that efficiently stores representations of multiple leaf nodes.

Abstract: During a restart process in which metadata is loaded from at least one of a plurality of storage devices into a cache, a storage controller is configured to generate an IO thread in response to the receipt of an IO request, identify at least one metadata page of the metadata that is used to fulfill the IO request, and generate a loading thread in association with the received IO thread that is configured to cause the storage controller to perform prioritized loading of the identified at least one page of the metadata into the cache. The loading thread is detachable from the IO thread such that, in response to an expiration of the IO thread, the loading thread continues to cause the storage controller to perform the prioritized loading until the loading of the at least one page of the metadata into the cache is complete.

Abstract: During a restart process in which metadata is loaded from at least one of a plurality of storage devices into a cache, a storage controller is configured to generate an IO thread in response to the receipt of an IO request, identify at least one metadata page of the metadata that is used to fulfill the IO request, and generate a loading thread in association with the received IO thread that is configured to cause the storage controller to perform prioritized loading of the identified at least one page of the metadata into the cache. The loading thread is detachable from the IO thread such that, in response to an expiration of the IO thread, the loading thread continues to cause the storage controller to perform the prioritized loading until the loading of the at least one page of the metadata into the cache is complete.