Emc IP Holding Company LLC

Emc Corporation

John Whitehead

Lijun Wang

Edward Cande

Bharat Sharma

Hualiang Xu

Systems and methods are provided herein for garbage collecting data previously tiered to cloud storage. A cloud object index can be generated and used to track objects stored in cloud storage. As objects within cloud storage are added or modified, the transactions can be tracked and the cloud object index can updated based on the activity. Expiration dates associated with cloud objects can be maintained in the cloud object index factoring in user defined retention periods, process defined retention periods for services like backup and snapshots, and regulatory defined retention periods depending on the type of data being tiered. Upon a determination that no active processes are linking to a cloud data object, that an expiration date has been met, and other custom factors, cloud objects can be removed from cloud storage permanently.

Garbage collection of data tiered 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.

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Ashland, MA, United States of America

John Whitehead