Abstract: A technique for performing deduplication on compressed data in a file system operates inline with storage requests, e.g., prior to writing compressed data specified in those storage requests to persistent file system structures. As requests to write data arrive, the file system compares those data with data already stored in the file system. If a match is found, metadata structures are written but compression and file system storage of the newly arrived data is avoided.

Abstract: A technique for managing a file system includes arranging a first set of multiple metadata elements at a first set of block locations and arranging a second set of multiple metadata elements at a second set of block locations. Each of the first set of metadata elements is related to a respective one of the second set of metadata elements to form a respective pair of metadata elements that the file system is configured to update together. The technique further includes backing the first set of block locations and the second set of block locations together on a single RAID stripe, such that updating each pair of metadata elements is achieved using a single stripe write.

Abstract: A technique for managing data storage provides multiple physical computing machines and block storage arranged in a NAS (network attached storage) cluster. The physical computing machines run NAS servers, with each NAS server including an FSDB (file system database) that identifies a set of file systems that belong to the NAS server. LUNs (Logical UNits) in the block storage provide backing store for the set of file systems of each NAS server. The NAS cluster manages access to a file system namespace for a set of file systems, including for example Distributed File System (DFS) typically accessed using the Server Message Block (SMB) protocol, by clients of different types, including for example clients using the Network File System (NFS) protocol.

Abstract: Archiving local logical units of data storage (LUNs) to cloud storage, wherein the local LUNs reside on local physical storage of a data storage system, includes establishing a mirror between a local LUN and a cloud-backed LUN backed by cloud physical storage of a cloud storage system, the mirror making data contents of the cloud-backed LUN identical to data contents of the local LUN. Once the mirror is established, then (a) a stub is deposited on the local LUN to direct subsequent IOs to the cloud-backed LUN, and (b) local physical storage of the local LUN is released for allocation to other local LUNs. Subsequent IOs to the local LUN are satisfied from the cloud-backed LUN. An archived LUN can be restored by a restore process.

Abstract: A method is used in managing recovery of file systems. A determination is made during recovery of a file system as to whether information required for recovering the file system is missing. Based on the determination, storage for a slice is provisioned. The slice is updated with the information required for recovering the file system. Recovery of the file system is performed.

Abstract: A technique for managing data storage provides multiple physical computing machines and block storage arranged in a NAS (network attached storage) cluster. The physical computing machines run NAS servers, with each NAS server including an FSDB (file system database) that identifies a set of file systems that belong to the NAS server. LUNs (Logical UNits) in the block storage provide backing store for the set of file systems of each NAS server. The NAS cluster performs a NAS server cloning operation in which an existing source NAS server is cloned in its entirety to create a separate clone NAS server, the operation automatically cloning all the separate file systems of the source NAS server and related metadata without a need for user involvement on a per-filesystem basis.

Abstract: A data processing system archives local snapshots of a primary storage object to cloud storage by dividing an address space of the snapshots into sequential chunks, and organizing the cloud storage into archived snapshots including sets of cloud objects created from respective modified chunks of local snapshots. The archived snapshots are organized into families each having a full snapshot and incremental snapshots. A new family is started by creating a synthesized full snapshot from the archived snapshots of a preceding family, which includes (1) for chunks whose data is contained within one cloud object of the preceding family, logically incorporating the cloud object into the synthesized full snapshot, and (2) for chunks whose data is contained within multiple cloud objects of the preceding family, coalescing the data of the cloud objects into a new cloud object and logically incorporating the new cloud object into the synthesized full snapshot.

Abstract: A method, computer program product, and computing system for storing a plurality of identifiers on a local data storage system. The plurality of identifiers locate a plurality of archived files at a plurality of defined remote addresses on a remote data storage system. The deletion of at least one of the plurality of identifiers is sensed, thus defining at least one deleted identifier. Temporal information of the at least one deleted identifier is compared to temporal information for a data protection operation performed on at least a portion of the local data storage system.

Abstract: A method, computer program product, and computing system for locally processing a plurality of data files stored on a local data storage system to identify an archivable file for storage on a remote data storage system. A remote tiering appliance is enabled to obtain the archivable file, wherein the remote tiering appliance stores the archivable file at a defined remote address on the remote data storage system. An identifier is received from the remote tiering appliance that locates the archivable file at the defined remote address on the remote data storage system. The identifier is stored on the local data storage system.

Abstract: A method, computer program product, and computing system for locally processing a plurality of data files stored on a local data storage system to effectuate the storage of one or more archivable files at one or more defined remote addresses on a remote data storage system. One or more identifiers, that locate the one or more archivable files at the one or more defined remote addresses on the remote data storage system, are stored on the local data storage system. A local database, that defines the one or more identifiers, is maintained on the local data storage system.

Abstract: Archiving local logical units of data storage (LUNs) to cloud storage, wherein the local LUNs reside on local physical storage of a data storage system, includes establishing a mirror between a local LUN and a cloud-backed LUN backed by cloud physical storage of a cloud storage system, the mirror making data contents of the cloud-backed LUN identical to data contents of the local LUN. Once the mirror is established, then (a) a stub is deposited on the local LUN to direct subsequent IOs to the cloud-backed LUN, and (b) local physical storage of the local LUN is released for allocation to other local LUNs. Subsequent IOs to the local LUN are satisfied from the cloud-backed LUN. An archived LUN can be restored by a restore process.

Abstract: Shipping local snapshots of logical units of data storage (LUNs) to cloud storage, wherein the local snapshots reside on local physical storage of a data storage system, includes replicating a baseline local snapshot of a LUN to a cloud-backed LUN backed by cloud physical storage of cloud storage system, and taking a first snapshot of the cloud-backed LUN to establish a baseline cloud-backed snapshot. For a subsequent local snapshot of the LUN, the method (1) identifies data content differences between the subsequent local snapshot and the baseline local snapshot, (2) updates the cloud-backed LUN by applying the data content differences, and (3) takes a second snapshot of the cloud-backed LUN, the second snapshot being a cloud-backed copy of the subsequent local snapshot and containing, in the cloud physical storage, (a) first blocks unique to the second snapshot and (b) second blocks shared with the baseline cloud-backed snapshot.

Abstract: A technique for managing host data in a data storage apparatus having a storage processor (SP) provides virtualized storage processors (VSPs) as substantially self-describing and independent entities. Each VSP has its own namespace, independent of the namespace of any other VSP. Each VSP also has its own network address. Hosts may thus access VSPs directly, without having to include path information relative to the SP on which the VSP is operated. VSPs can thus be moved from one physical SP to another with little or no disruption to hosts, which may continue to access the VSPs on the new SPs using the same paths as were used when the VSPs were running on the original SPs.

Abstract: A method is used in managing backing up of file systems. A portion of a file system that has changed since a last backup is determined. The file system includes a set of directory hierarchies. Each directory hierarchy includes a set of directories. Each directory of the set of directories includes a set of files. The portion of the file system is determined based on blocks of the file system that have changed since the last backup. The changed blocks are identified based on changes between at least two snapshot copies of the file system. Based on the changed blocks, a set of inodes of the file system that has changed since the last backup is determined. Based on the determination, a list of changed files associated with the set of inodes for performing backup of changed files of the file system is determined.

Abstract: A technique for restoring NAS (network attached storage) servers that have been archived to the cloud includes querying, by a local data storage system, a cloud-based data store to identify a set of cloud-backed volumes that belong to an archived NAS server to be restored. The technique further includes rendering the identified cloud-backed volumes as respective writable LUNs (Logical UNits), accessing the writeable LUNs by the local data storage system, and processing data on the writeable LUNs to operate file systems of the NAS server that are stored in the writeable LUNs.

Abstract: A technique for archiving NAS (network attached storage) servers includes replicating multiple locally-backed volumes, which support respective file systems of a NAS server, to respective cloud-backed volumes backed by a cloud-based data store. After replication has updated the cloud-backed volumes with contents from the locally-backed volumes, the technique further includes performing a group snapshot operation on the cloud-backed volumes. The group snapshot operation creates a point-in-time version of the cloud-backed volumes, which provides a replica of the NAS server archived in the cloud.

Abstract: A technique for managing cloud storage provides a unified framework that supports both block-type data, such as LUNs (Logical UNits) and volumes, and file-type data, such as files, and expresses both types of data in the form of objects, which form a common base for both types of data. The framework includes a single API (application program interface) for managing storage and retrieval of block-derived objects and file-derived objects from the cloud, e.g., from a cloud-based data store.

Abstract: A data storage system includes local data storage devices, network interface circuitry providing an interface to a cloud storage service, and processing circuitry configured and operative to: (1) form a first storage pool and associated first storage objects using first pool units of storage from the first storage pool, the first storage pool using the local data storage devices for underlying real storage, the first storage objects including both file-oriented objects and block-oriented objects; (2) form a second storage pool and associated second storage objects using second pool units of storage from the second storage pool, the second storage pool using the cloud storage service for underlying real storage; and (3) execute one or more of a tiering process and a backup process by which the first storage objects are migrated or copied to corresponding ones of the second storage objects for persistent storage by the cloud storage service.

Abstract: A method of protecting a filesystem against metadata corruption while maintaining high performance is provided. The method includes (a) receiving a storage command directing a computing device to store a block of file data to the filesystem and (b) in response: (1) writing the block to a data portion spanning a set of drives using a single-fault tolerant level of RAID, wherein writing the block includes performing exactly two write operations to the set of drives; and (2) writing filesystem metadata associated with the block to a metadata portion spanning a subset of the set of drives using a double-fault tolerant data redundancy scheme different than the single-fault tolerant level of RAID, the subset including at least three drives, the data and metadata portions being non-overlapping, wherein writing the metadata includes performing at least three write operations to the subset of the set of drives.

Abstract: A technique for supporting multi-tenancy in a NAS cluster provides a management database which tracks, for each tenant of the NAS cluster, a tenant-specific list of identifiers of NAS data nodes that are authorized to run NAS servers owned by respective tenants. In response to a request to run a NAS server owned by a particular tenant of the NAS cluster, the technique limits the scope of NAS data nodes on which the NAS server may be run to the ones identified in the tenant-specific list for that tenant in the management database. The management database thus determines where each tenant's NAS servers may be run, and participates in driving NAS cluster activities, such as NAS server provisioning, load balancing, and failover.