Abstract: A dataset is concurrently recovered after a server crash while the dataset is actively used for servicing client requests. In response to a reboot, records of not-yet-completed transactions in a transaction log are parsed to create a graph of dependencies between the transactions. Once this graph has been created, clients may access a specified block of the dataset after on-demand recovery of the specified block. The on-demand recovery is concurrent with a background recovery task that replays the not-yet-completed transactions in time order. The on-demand recovery uses the dependency graph to replay any and all transactions that support recovery of the specified block, so that recovery of the specified block includes update of other blocks to be consistent with the recovered block in accordance with the not-yet-completed transactions.

Abstract: Techniques are disclosed for measuring and attesting to service levels offered by a service provider in a computing system implemented with a distributed virtual infrastructure. In one example, a method comprises the following steps. Information is maintained relating to one or more services offered by one or more service providers in accordance with a distributed virtual infrastructure. One or more service level claims associated with the one or more services are validated. A subscriber is sent validation results for at least a portion of the one or more services.

Abstract: A storage processor isolates and classifies file system faults and inconsistencies to produce a fault tree for inline error recovery. The storage processor isolates the metadata objects or objects that have internal inconsistencies, the storage processor creates a fault tree to map the file system; or portion of the file system with the errors or inconsistencies and the metadata objects dependent upon those objects. Once the fault having been mapped, determine the complexity of recovering the branch of the fault tree with the error. If the error is not too complex, performing recovery of the metadata objects online otherwise taking the system offline for file system recovery.

Abstract: A storage processor includes storage for redundantly storing a log file of a journaling file system on a separate logical device from a primary copy of the log file and further provides for recovery of the file system upon failure of both the primary storage and the redundant storage storing the log file of the journaling file system by storing dirtied metadata objects in the cache of the storage processor to a vault area and then applying the stored dirtied metadata objects against the underlying persistent storage.

Abstract: Described are techniques for performing quota management in a distributed file system. An allocation quota specifies an upper limit of storage for allocation for a quota set of the distributed file system. The distributed file system includes metadata file system(s) and data file system(s). For files in the distributed file system, metadata is stored in one of the metadata file systems and file content data is stored in the data file systems. A quota coordinator partitions the allocation quota among the data file systems. The data file systems are allocators of storage and each receives a portion of the allocation quota specifying an upper limit of storage that the data file system has available for allocation for the quota set. Storage is allocated for client requests. The storage allocation is performed by each of the data file systems in accordance with the portion of the allocation quota assigned.

Abstract: Described are techniques for creating a snapshot of a distributed file system or a file thereof. The distributed file system includes metadata file systems storing metadata about files in the distributed file system and includes data file systems storing file content data. Quiescing is performed for requests affecting the distributed file system, or a file thereof, for which a snapshot is being created. A snapshot of metadata is obtained. For the distributed file system, this includes a snapshot of each metadata file system. For a file, this includes a snapshot of the file's metadata. A snapshot of file data is obtained. For distributed file systems, this includes a snapshot of each data file system. For a file, this includes a snapshot of the file's data. Unquiescing is performed for requests affecting the distributed file system, or the file thereof, upon successful completion of obtaining snapshots of metadata and file data.

Abstract: To preserve the contiguity of file map extents of a production file when making a series of snapshot copies, the snapshots share indirect blocks of the production file through virtual pointers. When a write to a data block of the production file is first done since the time of the most recent snapshot so that the most recent snapshot can no longer share one of the contiguous indirect blocks, a new indirect block is allocated to store the file mapping metadata for the most recent snapshot, and a virtual pointer for the snapshots is changed to point to this new indirect block. Therefore the change in the virtual pointer changes the file mapping metadata for any number of snapshots sharing the new indirect block so that the method is scalable.

Abstract: A system and method of operating a storage server in a data network for relocating one or more data blocks of a file, comprising creating a virtual block mapping pointer; and relocating one or more file system data.

Abstract: A file server provides access to a file system built on a logical volume of data storage. The file system includes multiple cylinder groups of file system blocks, and the logical volume includes slices of the cylinder groups. The file server has a storage reorganizer for identifying allocated file system blocks in a selected slice, and evacuating the identified allocated file system blocks from the selected slice. The selected slice is evacuated by reverse mapping each identified allocated block to identify a file to which the identified allocated block is allocated, allocating a new block in another slice, copying data from the identified allocated block to the new block, and substituting the new block for the identified allocated block in the file.

Abstract: Described are techniques for performing quota management in a distributed file system. An allocation quota specifies an upper limit of storage for allocation for a quota set of the distributed file system. The distributed file system includes metadata file system(s) and data file system(s). For files in the distributed file system, metadata is stored in one of the metadata file systems and file content data is stored in the data file systems. A quota coordinator partitions the allocation quota among the data file systems. The data file systems are allocators of storage and each receives a portion of the allocation quota specifying an upper limit of storage that the data file system has available for allocation for the quota set. Storage is allocated for client requests. The storage allocation is performed by each of the data file systems in accordance with the portion of the allocation quota assigned.

Abstract: A snapshot copy facility maintains information indicating ownership and sharing of child nodes in the hierarchy of a file between successive versions by delegating reference counts to the parent-child relationships between the nodes, as indicated by pointers in the parent nodes. When a child node becomes shared between a parent node of the production file and a parent node of a snapshot copy, the delegated reference count is split among the parent nodes. This method is compatible with a conventional data de-duplication facility, and avoids a need to update reference counts in metadata of child nodes of a shared intermediate node upon splitting the shared intermediate node when writing to a production file.

Abstract: In a file server, a file system is built upon a volume of data storage. The file system includes multiple cylinder groups. Each cylinder group includes file system blocks. The file system blocks include allocated blocks and free blocks. The volume includes slices of storage, and each slice stores at least one of the cylinder groups. A hierarchical slice map has a top level that includes a count of free blocks in the file system, an upper level that includes a count of free blocks in groups of the slices, an intermediate level that includes a count of the free blocks in sub-groups of the slices, and a bottom level that includes a count of the free blocks in each slice of storage. To find a free block for allocation to a file, the slice map hierarchy is searched in a top-down fashion.

Abstract: Storage tiering uses file system awareness of storage class for storage allocation or migration of a storage object from one class of storage to another. For example, the storage object is a production file system, a logical unit number (LUN) of storage, or a snapshot copy of the production file system or LUN. Each storage class may comprise a different back-end disk type, such as Fiber Channel, ATA, etc. Storage allocation or migration is based on storage class to implement a storage policy, such as: (a) move snapshots off the class of storage of the production object and onto a different class of storage; (b) direct new writes to a specified class of storage; or (c) writes targeting a particular storage object are targeted to a particular class of storage.

Abstract: This invention is a system and a method for operating a storage server in a data network using a new architecture. The method of creating the partial block map allows the snapshot writes on a direct mapped file. The method of reading data or writing data to the file created in direct mapping state and later converted to partial mapping state responsive to a copy on first write request by a client allocates new indirect block when needed to store the reference to newly allocated data block. The method of reading data from or writing data to the file in partial mapping state involves checking the mapping bit to find if the indirect block is in direct mapping state.

Abstract: Embodiments of the invention relate to maintaining reference counts in a file system to track when a block is available to be freed. When a snapshot copy of a file is created, rather than copying all the blocks of the file for the snapshot copy, the snapshot inode is given pointers to the blocks of the file. Rather than updating the reference counts for all these blocks to indicate that they are now in use by more than one file, the update of reference counts for at least some of these blocks may be deferred until a later time.

Abstract: This invention is a system and a method for operating a storage server to provide read or write access to a data in a data network using a new architecture. The method of creating virtual block mapping pointer in response to a request by a client of the storage server to de-duplicate the file system data block or to allow compression of one or more file system data blocks into one or more physical data blocks. Further, the method relocates one or more file system data blocks from one part of the file system address space to another by using one or more virtual block mapping pointers that provides the mapping information for the one or more file system data blocks that are being relocated. The virtual block mapping pointer allows relocating of file system data blocks by same number of metadata operations regardless of number of files sharing the block that are being relocated and the state of those blocks (compressed or not).

Abstract: Embodiments of the invention relate to maintaining reference counts in a file system to track when a block is available to be freed. When a snapshot copy of a file is created, rather than copying all the blocks of the file for the snapshot copy, the snapshot inode is given pointers to the blocks of the file. Rather than updating the reference counts for all these blocks to indicate that they are now in use by more than one file, the update of reference counts for at least some of these blocks may be deferred until a later time.

Abstract: A snapshot copy facility maintains information indicating block ownership and sharing between successive versions by delegating block reference counts to parent-child relationships between the file system blocks, as indicated by block pointers in inodes and indirect blocks. When a child block becomes shared between a parent block of the production file and a parent block of a snapshot copy, the delegated reference count is split among the parent blocks. This method is compatible with a conventional data de-duplication facility, and avoids a need to update block reference counts in block metadata of child blocks of a shared indirect block upon splitting the shared indirect block when writing to a production file.

Abstract: This invention is a system and a method for recovering and repairing a logical volume in a data storage environment using a new architecture. The method of recovering a logical volume enables mounting of a file system by instantiating only a single slice under the sparse volume and instantiating rest of the slices provisioned under the sparse volume in background by a asynchronous recovery process or on-demand by the clients of the file system issuing an I/O on the slice volume. The method of repairing a logical volume provides the ability to regenerate the metadata required to reconstruct the corrupted volume.

Abstract: A snapshot copy facility responds to a request for writing new data to a block of a production dataset by saving original data of the block, and writing the new data to the block of the production dataset and keeping a record of the blocks of the production dataset have been changed since the point in time when the snapshot copy was created. For detection of corruption of the snapshot metadata and for portability of the snapshot copy software, a sparse file is used for keeping a record of the blocks of the production dataset that have been changed since the snapshot. For “copy on first write” snapshots, the sparse file is a “write once read many” (WORM) file to store old data of blocks. For “remap on write” snapshots, the sparse file is a “read-write” (RW) file to which writes to the production file are stored.