Abstract: A technique for providing active-active access to pooled block-based objects and pooled file-based objects by multiple storage processors over distance in a metro-cluster includes virtualizing locally attached LUNs and making the virtualized LUNs available to all the storage processors in the metro-cluster. Storage pools and internal file systems operate on each of the storage processors and coordinate with one another to maintain consistent storage allocation and a consistent file system image across all storage processors in the metro-cluster. The resulting arrangement allows storage processors in the metro-cluster to access both block-based data objects and file-based data objects in an active-active manner, while maintaining consistency across all storage processors and allowing customers to benefit from the advantages of pooled data objects.

Abstract: Directory attributes are provided so that the time for creating an incremental backup of a file system by a scan of the file system tree is proportional generally to the number of files that change between backups instead of the number of files in the file system. A tree modification attribute indicates whether or not any file in a directory tree has changed since the last backup. If no file has changed in the directory tree, then the entire tree is skipped during the scan for changed files. In addition, a list is compiled of the files in the directory that represent branches having at least one changed file, so that the list is scanned instead of the directory entries. When a file is changed for the first time since the last backup, the file is queued so that the directory attributes are updated in a background process.

Abstract: An improved technique involves identifying the location of backed free blocks, i.e., blocks within an upper deck file system that have been provisioned from storage devices of a data storage system to a lower deck file system, allocated from the lower deck file system to the upper deck file system, and later freed from the upper deck file system. A storage processor accesses a set of data structures that identifies backed free blocks as opposed to free blocks that have not been written into and thus do not correspond to any allocated blocks in storage. Once the storage processor identifies the backed free blocks, the storage processor frees each block in the lower deck file system from which the respective backed free block was allocated. The storage processor then updates the set of data structures to indicate that the respective backed free block is now simply a free block.

Abstract: A technique performs virtual storage processor (VSP) failover. The technique involves accessing, by a first physical storage processor of the data storage apparatus, a VSP to create an operating environment for a host file system from the first physical storage processor. The technique further involves, after accessing the VSP to create the operating environment for the host file system from the first physical storage processor, detecting a failure of the first physical storage processor. The technique further involves accessing, in response to detecting the failure of the first physical storage processor and by a second physical storage processor of the data storage apparatus, the VSP to re-create the operating environment for the host file system from the second physical storage processor.

Abstract: Reclaiming storage from a file system hosting of storage objects includes assigning objects and respective files to version sets, each version set containing a primary object and respective snapshots. Each block of storage is associated with the version set of the file(s) that contain the block. Blocks residing in an extent that is to be reclaimed are identified, and for each block (i) an offset is obtained that specifies a location of the block in a file, (ii) files whose objects are assigned to the version set associated with the block are identified, (iii) a block pointer at the location in each of the identified underlying files is examined, and for each file whose block pointer points to the block, updating the block pointer to point to a new block location outside of the extent, to which the block is moved.

Abstract: A technique for managing storage tiering in a data storage apparatus operates at a fine level of granularity in response to write requests as blocks are allocated for writing. As write requests arrive or are otherwise processed by the data storage apparatus, the data storage apparatus identifies a quality of service to be provided for satisfying each write request and allocates a set of blocks from storage devices of storage tiers that provide the identified quality of service. The data storage apparatus may then store the information specified in the write request in the newly allocated blocks.

Abstract: A method is used in managing data deduplication in storage systems. Characteristics of first and second data objects are evaluated based on a set of deduplication policies. The first and second data objects are selected for deduplication. Based on the evaluation, deduplication performed on the first and second data objects is affected.

Abstract: A technique for managing failover from a first data storage system to a second data storage system includes configuring replication settings for data objects associated with VSPs (Virtualized Storage Processors) on a per-VSP basis, such that all of the data objects associated with each VSP share common replication settings. As the first data storage system operates a VSP, operations replicate data written to any of the data objects of the VSP to the second data storage system such that the second data storage system acquires and stores a replica of the VSP. In the event of a failure at the first data storage system, operations fail over the entire VSP, including all of its data objects, to the second data storage system, to restore host access to the data objects from the VSP replicas. A metro-cluster may be formed from multiple data storage systems that use this failover approach.

Abstract: A technique for performing synchronous replication on both block and file-based objects provides a data storage system that internally stores data objects (e.g., LUNs, file systems, block-based vVOLs (virtual volumes), file-based vVOLs, VMDKs, etc.) in the form of respective files, such that each file provides a realization of a data object. The data storage system maps each such file to a respective logical volume, and each logical volume provides a block-based interface. As the data storage system receives IO requests specifying data to be written to a data object, the data storage system renders the IO requests as block-based requests, regardless of whether the IO requests are themselves block-based or file-based. A block-based replication splitter intercepts the block-based requests directed to the logical volumes and performs block-based, synchronous replication on the requests, thereby achieving synchronous replication of both block-based objects and file-based objects in a single, unified architecture.

Abstract: A method is used in managing data inconsistencies in storage systems. A data inconsistency is detected in a portion of a file system. The portion of the file system includes a set of file system data blocks. The portion of the file system is recovered. The portion of the file system is validated by using information stored in a set of mapping pointers associated with the set of file system data blocks.

Abstract: Systems and methods of managing concurrent log writes to a transaction log are provided. A system may include: a transaction log residing on a non-volatile storage medium for logging metadata transactions of a file system; and a plurality of transaction log buffers, associated with the transaction log, residing in volatile memory. A first write operation may be initiated to write first contents of at least a first of the plurality of transaction log buffers to the transaction log. Concurrently to a performance of the first write operation, a second write operation may be initiated to write second contents of at least a second of the plurality of transaction log buffers to the transaction log.

Abstract: A data storage system includes storage devices and a processing subsystem executing software forming a lower-deck file system and an upper-deck file system. The lower-deck file system presents a volume file from which storage is provided to the upper-deck file system, and units of storage of the storage devices are allocable to the upper-deck file system but are not reserved to it. The volume file is thinly provisioned, and additional units of storage are added dynamically to increase its allocated size in response to demand from the upper-deck file system. The lower-deck file system operates in a mapped mode in which a block address in the lower-deck file system is obtained by a generally arbitrary mapping (e.g., an Inode/IB tree) of a block address in the volume file.

Abstract: A technique for managing synchronous replication and asynchronous replication of both block-based objects and file-based objects employs a common replication session manager configured from a common GUI application. The replication session manager can access different settings for different data objects (e.g., LUNs, file systems, block-based vVOLs (virtual volumes), file-based vVOLs, VMDKs, etc.), with replication settings maintained on a per-data-object basis. The replication session manager can also orchestrate synchronous and/or asynchronous replication sessions, failover, and/or recovery, for any given data object in accordance with the particular data-object-specific settings established for that object.

Abstract: A technique for managing access to files by different data storage systems includes a data storage system generating an E-FSID (export FSID) for a file system in addition to a conventional FSID and providing the E-FSID in file handles that the data storage system generates for providing clients with access to the file system. The E-FSID is shared between/among different data storage systems, with each data storage system including data for cross-referencing the E-FSID to a respective local FSID for the file system. Because the E-FSID for a file is the same across different data storage systems, file handles continue to work after failover, migration, and other transitions.

Abstract: A method, computer program product, and computing system for grouping storage blocks within a file system into a plurality of storage pools including a free-backed storage pool, a free-unbacked storage pool, and an allocated-backed storage pool. The free-backed storage pool identifies unused storage blocks within the file system that are already associated with physical storage space within a backend storage system. The free-unbacked storage pool identifies unused storage blocks within the file system that are not yet associated with physical storage space within the backend storage system. The allocated-backed storage pool identifies used storage blocks within the file system that are already associated with physical storage space within the backend storage system. A request is received for one or more unused storage blocks within the file system.

Abstract: A method is used in managing files of file systems. A group transaction record for an indirect data block of a file of a file system is created. The indirect data block of the file includes a set of data blocks of the file. A set of transaction entries is added to the group transaction record. Each transaction entry of the set of transaction entries includes information regarding an operation performed on a data block of the set of data blocks. The group transaction record is stored in a journal. The journal includes metadata transactions upon a plurality of files of a plurality of file systems.

Abstract: A technique provides virtual storage processor (VSP) mobility with induced file system format migration. The technique involves receiving a command specifying (i) a source VSP which includes source file systems which store data in a source file system format, (ii) a destination, and (iii) a destination file system format. The technique further involves forming, in response to the command, a destination VSP which includes destination file systems. The technique further involves copying, while the source VSP is accessed by a set of host computers, data from the source file systems of the source VSP to the destination file systems of the destination VSP. The destination file systems store the copied data in the destination file system format. The technique further involves synchronizing, after the data is copied from the source file systems to the destination file systems, state changes between the source VSP and the destination VSP.

Abstract: A technique for managing replication of VSPs (Virtualized Storage Processors) proceeds on a per-VSP basis by (i) identifying the data objects associated with a VSP, (ii) establishing a common set of replication settings across all of the data objects associated with the VSP, and (iii) replicating the VSP by replicating each of the identified data objects associated with the VSP in accordance with the common set of replication settings established across all of the data objects associated with the VSP. The technique avoids the need for administrators to separately configure and manage replication on large numbers of individual data objects and thus reduces administrative burdens.

Abstract: A technique performs virtual storage processor (VSP) load balancing. The technique involves receiving a VSP move command to load balance a particular VSP from a source physical storage processor to a destination physical storage processor. The technique further involves relinquishing, by the source physical storage processor, access to a set of VSP definitions that define the particular VSP. The technique further involves obtaining, by the destination physical storage processor, access to the set of VSP definitions that define the particular VSP, the particular VSP being load balanced from the source physical storage processor to the destination physical storage processor upon the destination physical storage processor obtaining access to the set of VSP definitions that define the particular VSP.

Abstract: An improved technique for a data storage apparatus that combines both block-based and file-based functionality in a unified data path architecture. The improved technique brings together IO processing of block-based storage systems and file-based storage systems by expressing both block-based objects (e.g., LUNs) and file-based objects (e.g., file systems) in the form of files. These files are parts of an underlying, internal set of file systems, which are stored on a set of storage units served by a storage pool. Because block and file-based objects are all expressed as files of this set of file systems, a common set of services can be applied across block-based and file-based objects. Also, storage units released by any file or files of the underlying, internal set of file systems can be reused by any other file or files, regardless of whether the files represent block-based objects or file-based objects. Inefficiencies of stranded storage are thus greatly reduced or eliminated altogether.