Hitachi Data Systems Engineering UK Limited

Hitachi Vantara Corporation

Bluearc UK Limited

Neil Berrington

Christopher J Aston

Daniel J N Picken

Trevor Edward Willis

Gaurav Sharma

Mark Stephen Laker

Carlo F Garbagnati

Namita Lal

Shmuel Shottan

Martin A Dorey

Simon L Benham

Hoc Dinh Ngo

John C Holtom

A file cloning process allows for quickly cloning files within a filesystem, such as when a user makes a copy of a directory containing files and subdirectories of files. A priority based main queue is filled by a depth first traversal of the directory to be copied with work items corresponding to files and subdirectories. Worker threads refer to the main queue for file cloning, subdirectory copying and directory traversal. Files that have not been modified since a most recent checkpoint are cloned without issuing a checkpoint request. Files that have been modified since the most recent checkpoint are moved to a delay queue. Once a checkpoint of the file system completes, the files in the delay queue are then moved to the main queue to retry cloning thereof. A secondary queue is also provided to prevent worker threads from becoming deadlocked in the main queue.

System for queue based object cloning

A deduplication system and method involves interaction between a software-based system that manages the overall background deduplication process and a hardware-based system that includes a hardware-based filesystem manager and a hash generator. A filesystem checkpoint mechanism is leveraged to manage the background deduplication process and also to reduce processing complexity with respect to identifying chunks that are candidates for deduplication and processing such chunks.

System and method for managing deduplication using checkpoints in a file storage system

Embodiments of the present invention allow multiple checkpoints to be taken so that multiple versions of the filesystem, including a working version and at least two checkpoint versions, can be maintained over time. Specifically, at least three 'superblock' root structures are used to manage multiple instantiations of the filesystem. The superblocks are preferably stored in fixed locations within the storage system for easy access, although they may alternatively be stored in other ways. The number of superblocks may be fixed or variable.

Multi-way checkpoints in a data storage system

A file cloning mechanism allows for quickly creating copies (clones) of files within a filesystem, such as when a user makes a copy of a file. In exemplary embodiments, a clone of a source object is at least initially represented by a structure containing references to various elements of the source object (e.g., indirect onodes, direct onodes, and data blocks). Both read-only and mutable clones can be created. The source file and the clone initially share such elements and continue to share unmodified elements as changes are made to the source file or mutable clone. None of the user data blocks or the metadata blocks describing the data stream (i.e., the indirect/direct onodes) associated with the source file need to be copied at the time the clone is created. At appropriate times, cloned files may be 'de-cloned.'

File cloning and de-cloning in a data storage system

A multi-tiered filesystem integrates multiple types of storage devices into a contiguous filesystem storage space having regions associated with two or more tiers of storage.

Multi-tiered filesystem

Embodiments of the present invention provide for compression of files in a filesystem. In embodiments of the present invention, a file is logically partitioned into chunks and each chunk is compressed, such that a request involving a portion of a file can be satisfied by reading and decompressing only the compressed chunk(s) corresponding to that portion.

Growing community of inventors

San Jose, CA, United States of America

Neil Berrington