Abstract: Technology described herein can perform deletion of a snapshot or portion thereof. In an embodiment, a system can comprise a processor and a memory that stores executable instructions that, when executed by the processor, facilitate performance of operations. The operations can comprise, to delete a snapshot, or a portion of a snapshot, of a real filesystem, reading an inode mapping file (IMF) of the snapshot that indexes a virtual inode number (VIN) corresponding to a real inode. The operations further can comprise identifying the real inode of the snapshot referenced by the VIN, identifying a file object corresponding to the real inode, and deleting the file object from the snapshot.

Abstract: Technology described herein can perform deletion of a snapshot or portion thereof. In an embodiment, a system can comprise a processor and a memory that stores executable instructions that, when executed by the processor, facilitate performance of operations. The operations can comprise, to delete a snapshot, or a portion of a snapshot, of a real filesystem, reading an inode mapping file (IMF) of the snapshot that indexes a virtual inode number (VIN) corresponding to a real inode. The operations further can comprise identifying the real inode of the snapshot referenced by the VIN, identifying a file object corresponding to the real inode, and deleting the file object from the snapshot.

Abstract: Techniques for scavenging blocks may include: determining, in accordance with a selected option, a set of candidate upper deck file systems, wherein at least a first of the candidate upper deck file systems has storage allocated from at least one block of a lower deck file system; and performing, in accordance with the selected option, scavenging of the set of candidate upper deck file systems to attempt to free blocks of the lower deck file system. Scavenging may include issuing a request to perform hole punching of a backed free block of the first candidate upper deck file system, wherein the backed free block has first provisioned storage that is associated with a block of the lower deck file system. The selected option may be one of multiple options each specifying a different candidate set of upper deck file systems upon which hole punching is performed when selected.

Abstract: An apparatus in one embodiment comprises a storage system having at least first and second storage tiers each comprising a plurality of storage devices. The first storage tier implements a file system having a user visible name space and a corresponding hidden data store. The second storage tier implements a cloud-based object store. The storage system is configured to controllably relocate files from the hidden data store of the file system of the first storage tier to the cloud-based object store of the second storage tier. In conjunction with the relocation of a given one of the files, the given file is replaced in the hidden data store with a corresponding stub providing user access via the user visible name space to an object comprising the given file in the cloud-based object store of the second storage tier. The controllable relocation is illustratively performed in accordance with one or more configured policies.

Abstract: A method is used in managing migration of virtual file servers. The method migrates a virtual file server from a source storage processor to a destination storage processor in a storage system. The storage system includes the source and the destination storage processors. The virtual file server comprises a root file system, a configuration file system, and a set of user file systems. The method enables concurrent access to the root file system from both source and destination storage processors during the migration until the set of user file systems is migrated from the source storage processor to the destination storage processor.

Abstract: Techniques for scavenging blocks may include: determining, in accordance with a selected option, a set of candidate upper deck file systems, wherein at least a first of the candidate upper deck file systems has storage allocated from at least one block of a lower deck file system; and performing, in accordance with the selected option, scavenging of the set of candidate upper deck file systems to attempt to free blocks of the lower deck file system. Scavenging may include issuing a request to perform hole punching of a backed free block of the first candidate upper deck file system, wherein the backed free block has first provisioned storage that is associated with a block of the lower deck file system. The selected option may be one of multiple options each specifying a different candidate set of upper deck file systems upon which hole punching is performed when selected.

Abstract: A method, computer program product, and computer system for receiving, at a computing device, an I/O request directed to a compressed data portion of a storage system. It may be determined whether the I/O request includes one of a first portion of information and a second portion of information. An address of the compressed data portion may be obtained via downward mapping if the I/O request includes the first portion of information. The address of the compressed data portion may be obtained via upward mapping if the I/O request includes the second portion of information. The I/O request may be executed at the compressed data portion.

Abstract: Techniques for scavenging blocks may include: determining, in accordance with a selected option, a set of candidate upper deck file systems, wherein at least a first of the candidate upper deck file systems has storage allocated from at least one block of a lower deck file system; and performing, in accordance with the selected option, scavenging of the set of candidate upper deck file systems to attempt to free blocks of the lower deck file system. Scavenging may include issuing a request to perform hole punching of a backed free block of the first candidate upper deck file system, wherein the backed free block has first provisioned storage that is associated with a block of the lower deck file system. The selected option may be one of multiple options each specifying a different candidate set of upper deck file systems upon which hole punching is performed when selected.

Abstract: Methods and apparatus are provided for reporting space savings due to data reduction in storage systems. An exemplary method comprises establishing a leaf pointer for a plurality of allocation units of data in a storage system; for at least a first allocation unit of data matching a second allocation unit of data, replacing the leaf pointer for the first allocation unit with a deduplication pointer to the leaf pointer of the second allocation unit; determining a total number of pointers as a sum of a number of the leaf pointers and a number of the deduplication pointers; determining a difference between the total number of pointers and the number of leaf pointers; and providing a data reduction attributed to deduplication based on the difference. The allocation units of data are optionally also compressed. Data reduction attributed to the compression can optionally be determined independent of the data reduction attributed to the deduplication.

Abstract: Methods and apparatus are provided for reporting space savings due to pattern matching in storage systems. An exemplary method comprises, when a given allocation unit in a storage system matches one or more predefined patterns, (i) setting a corresponding pattern flag for the given allocation unit, and (ii) incrementing at least one pattern counter; generating at least one snapshot of at least a portion of a file comprising the given allocation unit; and determining a data reduction attributed to pattern matching based on the at least one pattern counter, wherein the one or more predefined patterns in the at least one snapshot are excluded from the data reduction attributed to pattern matching.

Abstract: There are disclosed techniques for reporting space savings due to compression in storage systems. In one embodiment, the techniques comprise receiving a request to write data to a data storage system. The techniques also comprise performing a compression of the data associated with the request. The techniques further comprise determining a difference between a number of allocation units needed if no compression of the data associated with the request and a number of allocation units allocated to service the compressed data associated with the request. The techniques still further comprise providing a data reduction attributed to compression based on the difference.

Abstract: Techniques for scavenging blocks may include: determining, in accordance with a selected option, a set of candidate upper deck file systems, wherein at least a first of the candidate upper deck file systems has storage allocated from at least one block of a lower deck file system; and performing, in accordance with the selected option, scavenging of the set of candidate upper deck file systems to attempt to free blocks of the lower deck file system. Scavenging may include issuing a request to perform hole punching of a backed free block of the first candidate upper deck file system, wherein the backed free block has first provisioned storage that is associated with a block of the lower deck file system. The selected option may be one of multiple options each specifying a different candidate set of upper deck file systems upon which hole punching is performed when selected.

Abstract: A method is used in managing migration of virtual file servers. The method migrates a virtual file server from a source storage processor to a destination storage processor in a storage system. The storage system includes the source and the destination storage processors. The virtual file server comprises a root file system, a configuration file system, and a set of user file systems. The method enables concurrent access to the root file system from both source and destination storage processors during the migration until the set of user file systems is migrated from the source storage processor to the destination storage processor.

Abstract: Techniques for providing encryption of individual data objects in a data storage system include realizing data objects in the form of container files stored in a set of file systems, and encrypting individual ones of the data objects by encrypting the container files realizing the data objects using encryption keys associated with the individual data objects. By independently encrypting the container files that realize individual data objects, the disclosed system provides per-data object encryption. Each data object may be encrypted differently, e.g. using a different encryption key, even when multiple data objects are hosted over the same storage device or over a shared set of storage devices.

Abstract: This invention is a system and a method for operating a storage server in a data network using a new architecture. The system of operating a storage server includes a secondary storage that archives or stores a data object in transformed form such that the clients of the storage server can no longer access the data directly. The method of accessing the data object that is archived or transformed in a different form to the secondary storage includes recalling only those data blocks that are required for read or write operation.