Abstract: An apparatus comprises at least one processing device configured to receive unmap requests for freeing up data previously written to one or more storage regions of at least one storage device of a distributed storage system, the unmap requests being received from two or more write cache instances of two or more storage nodes of the distributed storage system. The processing device is also configured to identify at least a subset of the unmap requests which are directed to a given storage region of the at least one storage device. The processing device is further configured to provide the subset of the unmap requests to at least one storage controller associated with the at least one storage device of the distributed storage system responsive to determining that at least one designated unmap condition has been met.

Abstract: A data deduplication process is performed in a storage system which includes storage nodes, and storage control nodes which can access data directly from each storage node. A first storage control node sends a message to a second storage control node to initiate a deduplication process with respect to a given data block and an original data block owned by the second storage control node. The second storage control node increments a reference counter associated with the original data block, and sends a message to the first storage control which includes metadata. The first storage control node uses the metadata to read the original data block from a given storage node, performs a data compare process to determine whether the given data block matches the original data block, and creates a reference to the original data block, if the given data block matches the original data block.

Abstract: Techniques described herein relate to a method for performing computational offloads for composed information handling systems. The method includes obtaining, by a system control processor associated with a composed information handling system, a computational offload request associated with a dataset from an application executing on an at least one compute resource set; in response to obtaining the computational offload request: identifying a dataset location associated with the dataset in the composed information handling system; identifying resources of the composed information handling system capable of performing the computational offload request; selecting a resource of the resources to perform the computational offload; and initiating performance of the computational offload request on the selected resource.

Abstract: Techniques are provided to facilitate access to fragmented snapshot data. For example, a storage control system generates a snapshot data structure of a storage volume. The snapshot data structure comprises plurality of nodes comprising a volume node and one or more snapshot nodes, the volume node is configured to store new and updated data that is written to logical offsets of the storage volume, and the one or more snapshot nodes comprise point-in-time copies of data of the storage volume taken at different times. The storage control system adds an entry for the volume node in a metadata structure associated with the snapshot data structure, wherein the entry comprises a reference to a physical location of data held by a given one of the snapshot nodes at a given logical offset of the storage volume.

Abstract: Techniques are provided to manage data on shutdown of a data storage system. For example, a method comprises initiating a process to shut down a data storage system which comprises storage devices that store data associated with one or more non-persistent logical storage resources of a virtual storage layer which is configured by the data storage system. In response to initiating the process to shut down the data storage system, the method comprises: storing configuration data associated with the virtual storage layer, the configuration data comprising unique identifiers associated with the one or more non-persistent logical storage resources; and performing a data backup process to persistently store a copy of the data associated with the one or more non-persistent logical storage resources to a backup storage system.

Abstract: Techniques are provided for managing a dynamic reserve capacity of a block storage system. A storage control system partitions a storage capacity of at least one storage device into a plurality of blocks for storing data. A data access operation is performed by the storage control system which results in invalidating at least a portion of data stored in a given block. In response to the invalidating, the storage control system determines a degree of invalid data in the given block, and compares the determined degree of invalid data to a utilization threshold. The storage control system designates the given block as fully utilized in response to determining that the degree of invalid data does not exceed the utilization threshold, and designates a capacity of the given block that is occupied by the invalid data to be part of a reserve capacity of the at least one storage device.

Abstract: An apparatus comprises a processing device configured to receive a request to perform merging in a snapshot mapping structure comprising objects representing a given storage volume and its snapshots. The objects are organized in a tree structure representing data dependencies between the given storage volume and its snapshots. The processing device is also configured to analyze the snapshot mapping structure to identify ones of the objects that are candidates for deletion and to determine merge groups. A given one of the merge groups includes (i) at least a subset of the objects identified as candidates for deletion and (ii) a given object that is a child object of at least one of the subset of the objects identified as candidates for deletion. The processing device is further configured to perform merging in the snapshot mapping structure by merging data items in the given merge group to one of its objects.

Abstract: An apparatus comprises a processing device configured to receive a write request to write a given portion of data to a storage system comprising a multiple-instance write cache, the multiple-instance write cache comprising a first write cache instance that utilizes replica-based data protection and a second write cache instance that utilizes data striping-based data protection, and to determine a size of the given data portion and to compare the size of the given data portion to at least one size threshold. The processing device is also configured, responsive to a first comparison result, to write the given data portion to the first write cache instance. The processing device is further configured, responsive to a second comparison result different than the first comparison result, to write at least part of the given data portion to the second write cache instance.

Abstract: Techniques are provided for implementing and managing a multi-modal write cache for a data storage system. For example, a storage control system is configured to perform a write caching method which comprises the storage control system receiving an input/output (I/O) write request from a client application to write data to a primary storage volume, comparing a current I/O workload associated with the client application to an I/O workload threshold, and writing the data of the I/O write request to one of (i) a persistent write cache in a persistent storage volume and (ii) a non-persistent write cache in a non-persistent storage volume, based at least in part on a result of comparing the current I/O workload to the I/O workload threshold.

Abstract: An apparatus comprises a processing device configured to initiate garbage collection for data pages stored in local storage of a storage node of a storage system. The processing device is also configured to determine, for a given data page stored in the local storage of the storage node, a validity score characterizing a size of changed data in the given data page, and to compare the validity score for the given data page to at least one designated threshold. The processing device is further configured to update a given page object for the given data page in an object store of persistent storage responsive to a first comparison result, and to generate, in the object store of the persistent storage, a page delta object for the given data page responsive to a second comparison result, the page delta object comprising the changed data in the given data page.

Abstract: Techniques for in-band modification of event notification preferences for server events are provided. One method comprises obtaining an event notification; providing the event notification to a target device based on rule-based preferences of a user associated with the target device; obtaining a reply to the event notification from the target device, wherein the reply comprises event preferences of the user; and updating the rule-based preferences of the user based on the event preferences of the user. The updating of the rule-based preferences of the user may comprise creating, modifying and/or canceling at least one event preference rule of the user. A plurality of the event preference rules matching the event notification may be resolved in an order determined by one or more event preference rule resolution criteria.

Abstract: An apparatus comprises a processing device configured to receive a write request to write a given portion of data to a storage system comprising a multiple-instance write cache, the multiple-instance write cache comprising a first write cache instance that utilizes replica-based data protection and a second write cache instance that utilizes data striping-based data protection, and to determine a size of the given data portion and to compare the size of the given data portion to at least one size threshold. The processing device is also configured, responsive to a first comparison result, to write the given data portion to the first write cache instance. The processing device is further configured, responsive to a second comparison result different than the first comparison result, to write at least part of the given data portion to the second write cache instance.

Abstract: Techniques are provided to manage data on shutdown of a data storage system. For example, a method comprises initiating a process to shut down a data storage system which comprises storage devices that store data associated with one or more non-persistent logical storage resources of a virtual storage layer which is configured by the data storage system. In response to initiating the process to shut down the data storage system, the method comprises: storing configuration data associated with the virtual storage layer, the configuration data comprising unique identifiers associated with the one or more non-persistent logical storage resources; and performing a data backup process to persistently store a copy of the data associated with the one or more non-persistent logical storage resources to a backup storage system.

Abstract: Techniques are provided for managing metadata of a storage system. A storage control system manages a storage metadata structure which comprises metadata items for accessing data items in a storage system comprising a persistent write cache and a primary storage. The storage metadata structure comprises a first metadata structure that is configured to organize metadata items received from the write cache at a first granularity, and a second metadata structure that is configured to organize metadata items received from the first metadata structure at a second granularity, wherein the second granularity is greater than the first granularity. The storage control system utilizes the storage metadata structure to access data items in the persistent write cache and the primary storage.

Abstract: An apparatus comprises a processing device configured to receive a write request to write a given portion of data to a storage system comprising a multiple-instance write cache, the multiple-instance write cache comprising a first write cache instance that utilizes replica-based data protection and a second write cache instance that utilizes data striping-based data protection, and to determine a size of the given data portion and to compare the size of the given data portion to at least one size threshold. The processing device is also configured, responsive to a first comparison result, to write the given data portion to the first write cache instance. The processing device is further configured, responsive to a second comparison result different than the first comparison result, to write at least part of the given data portion to the second write cache instance.

Abstract: An apparatus comprises a processing device configured to initiate garbage collection for data pages stored in local storage of a storage node of a storage system. The processing device is also configured to determine, for a given data page stored in the local storage of the storage node, a validity score characterizing a size of changed data in the given data page, and to compare the validity score for the given data page to at least one designated threshold. The processing device is further configured to update a given page object for the given data page in an object store of persistent storage responsive to a first comparison result, and to generate, in the object store of the persistent storage, a page delta object for the given data page responsive to a second comparison result, the page delta object comprising the changed data in the given data page.

Abstract: A storage control system receives a request to access target data and searches a primary metadata structure to find an associated metadata entry. The primary metadata structure comprises a log-structured merge tree comprising a first level of segments which comprises a group of segments having an associated group filter, and individual filters associated with respective segments of the group of segments. The storage control system searches the primary metadata structure by performing a lookup operation using the group filter to determine whether the associated metadata entry is potentially present in a given segment of the group of segments, and performing a lookup operation using the individual filters to identify the given segment of the group of segments which potentially includes the metadata entry, when the metadata entry is determined to be potentially present in a given segment of group of segments, using the group filter.

Abstract: An apparatus comprises a processing device configured to receive, from one of two or more storage nodes of a software-defined storage system comprising a write cache and persistent storage, a request to read a given portion of data. One or more portions of data in the persistent storage are also stored as read-only data in local storage of virtual computing instances implementing the storage nodes. The processing device is configured to read the given portion of data from the local storage of the virtual computing instances responsive to determining that the given portion of data is part of the read-only data in the local storage of the virtual computing instances, and to read the given portion of data from the write cache or persistent storage responsive to determining that the given portion of data is not part of the read-only data in the local storage of the virtual computing instances.

Abstract: A storage control system manages a storage metadata structure which comprises first and second tree structures. The first tree structure is configured to accumulate metadata entries associated with newly written data items, and sort the accumulated metadata entries by index keys. The second tree structure is configured to organize metadata entries using an index structure that enables random-access to the metadata entries using the index keys. The storage control system performs a merging process to merge metadata entries in leaf levels of the first and second tree structures, and performs a tree construction process to construct a third tree structure by populating a leaf level of the third tree structure with merged metadata entries from the leaf levels of the first and second tree structures. The storage metadata structure is updated to comprise the first tree structure, and the third tree structure in place of the second tree structure.

Abstract: A storage control system manages a storage metadata structure which comprises first and second tree structures. The first tree structure is configured to accumulate metadata entries associated with newly written data items, and sort the accumulated metadata entries by index keys. The second tree structure is configured to organize metadata entries using an index structure that enables random-access to the metadata entries using the index keys. The storage control system performs a merging process to merge metadata entries in leaf levels of the first and second tree structures, and performs a tree construction process to construct a third tree structure by populating a leaf level of the third tree structure with merged metadata entries from the leaf levels of the first and second tree structures. The storage metadata structure is updated to comprise the first tree structure, and the third tree structure in place of the second tree structure.