Emc IP Holding Company LLC

Emc Corporation

Hualiang Xu

Edward Cande

Lijun Wang

Jonathan Mark Walton

Bharat Sharma

John Whitehead

Yi Li

Systems and methods are provided herein for establishing data constructs necessary for efficient and transparent tiering of data from local storage to cloud storage, and there use in transferring data to and from cloud storage. Files data can split into chunks and stored as individual objects in cloud storage. A stub file can replace the local file in local storage and describe a mapping of cloud objects that contain data to specific regions of the file. Upon creation of the stub and transfer of data to cloud storage, local storage capacity previously dedicated to file data can be freed for other uses.

Data and metadata structures for use in tiering data to cloud storage

Systems and methods are provided herein for writing back data to files tiered in cloud storage. Files tiered to cloud storage can be stored in chunks where each chunk is stored as a distinct cloud object and where each cloud object is mapped to known offset regions of a file and the mapping is stored in local storage within a stub file. If the file is modified locally, e.g., a write has occurred, the offset range associated with the write can be used to determine which cloud object associated with the file is being modified. A new cloud object can be stored with the write data, while the previous cloud object is retained in cloud storage. The mapping, stored within the stub file can updated to reference the new cloud object for the region of the file that was modified. In addition, mapping can be retained for the previous version of the file allowing for efficient recall of past versions of files.

Writing back data to files tiered in cloud storage

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Westborough, MA, United States of America

Hualiang Xu