Microsoft Technology Licensing, LLC

Kashif Hasan

Ran Kalach

Chun Ho Cheung

Abhishek Gupta

Paul Adrian Oltean

James Robert Benton

Jason Daniel Shay

Spencer Alan Bishop

Fenghua Yuan

Ping Xie

Ahmed El-Shimi

Daniel Hefenbrock

A system hosts a file system representing a replica of file systems hosted on a plurality of nodes, each node storing data on a first storage medium. The system stores data on a second storage medium that is slower than the first storage medium. The system stores on the second storage medium a file received from one of the nodes when the file remains un-accessed by the nodes for a predetermined period of time. The first storage medium on the plurality of nodes stores a pointer to the file and not the data content of the file stored on the second storage medium. The system provides the file from the second storage medium to the first storage medium on one of the nodes while providing the plurality of nodes read and write access to the file stored on the second storage medium using the pointer on the first storage medium.

Reliable hierarchical storage management with data synchronization

The subject disclosure is directed towards partially recalling file ranges of deduplicated files based on tracking dirty (write modified) ranges (user writes) in a way that eliminates or minimizes reading and writing already-optimized adjacent data. The granularity of the ranges does not depend on any file-system granularity for tracking ranges. In one aspect, lazy flushing of tracking data that preserves data-integrity and crash-consistency is provided. In one aspect, also described is supporting granular partial recall on an open file while a data deduplication system is optimizing that file.

Granular partial recall of deduplicated files

The subject disclosure is directed towards a data storage service that uses hash values, such as substantially collision-free hash values, to maintain data integrity. These hash values are persisted in the form of mappings corresponding to data blocks in one or more data stores. If a data error is detected, these mappings allow the data storage service to search the one or more data stores for data blocks having matching hash values. If a data block is found that corresponds to a hash value for a corrupted or lost data block, the data storage service uses that data block to repair the corrupted or lost data block.

Data error detection and correction using hash values

The subject disclosure is directed towards transforming a file having at least one undeduplicated portion into a fully deduplicated file. For each of the at least one undeduplicated portion, a deduplication mechanism defines at least one chunk between file offsets associated with the at least one undeduplicated portion. Chunk boundaries associated with the at least one chunk are stored within deduplication metadata. The deduplication mechanism aligns the at least one chunk with chunk boundaries of at least one deduplicated portion of the file. Then, the at least one chunk is committed to a chunk store.

Optimization of a partially deduplicated file

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Snoqualmie, WA, United States of America

Kashif Hasan