Microsoft Technology Licensing, LLC

Christophe Franck Robert

Sarosh Cyrus Havewala

Guhan Suriyanarayanan

Shobana Balakrishnan

Dan Teodosiu

Nikolaj Skallerud Bjorner

Ahmed Hassan Mohamed

David Golds

Ahmed H Microsoft Corporation Mohamed

Files on a computing device are defined to include data and metadata relating to the data. Data from each file has been removed therefrom and stored at an alternate location and the file is in a reduced, ghosted form. Each of at least some ghosted files has been fully or partially reconstituted for use by retrieving the data thereof from the alternate location and associating such retrieved data with such ghosted file to form the reconstituted file. Upon receiving a trigger based on a triggering event, files are selected from among the fully and partially reconstituted files and never-ghosted files based on first predetermined selection criteria, and each of at least some of the selected files are re-ghosted.

Moving data from file on storage volume to alternate location to free space

I/O request data for user-mode programs is recorded into a log, which later allows the I/O requests to be replayed. By substantially exact replay, tests are performed with different versions/combinations of kernel components using the same I/Os as when recorded. A user-mode record/replay program and kernel-mode filter driver record a program's I/O requests, such as data I/O request packet (IRP) data received by the filter driver. While recording, tests exclude IRPs not directly resulting from program requests. Recorded I/O request data is maintained in log file records. At replay time, the records are read and corresponding I/O requests sent towards the storage volume as if requested by the original program. Tables are maintained for information relevant to the replay context, such as file handles, file IDs, and short names that vary from the record context. Substitution from the tables allows I/O requests to be replayed as originally issued.

Method and system for recording and replaying input-output requests issued by a user-mode program

A computing device has a storage volume, a file system managing the storage volume, and a file stored on the storage volume and accessed by such file system. The file system receives an open command for the file from an application, notes that the file has been ghosted in that data of the file has been moved to an alternate location, and returns an error. The returned error is intercepted and the file system is commanded to retrieve ghosting information from the ghosted file. A handle corresponding to the ghosted file is delivered to the application, and a read command for the file is received from the application, including the handle, an offset, and a read length. Reconstituting of the ghosted file is initiated based on the data thereof at the alternate location, and after reconstituting the read command is responded to with the data requested.

To reconstitute a ghosted file for use, a single ghosting filter on a computing device locates ghosting information in the metadata of the ghosted file and locates within the ghosting information an identification of a particular ghosting manager of the computing device, where the identified ghosting manager is responsible for the ghosted file. Thereafter, the ghosting filter communicates to the identified ghosting manager a request to obtain data of the ghosted file from a corresponding alternate location, and the identified ghosting manager does in fact obtain such requested data from such alternate location. Upon receiving the requested data of the ghosted file from the identified ghosting manager, then, the ghosting filter reconstitutes the received data to the ghosted file. The single ghosting filter is generic to all of the ghosting managers of the computing device.

A ghosting filter on a computing device receives a read command for a requested range of data of a ghosted file. The requested range is categorized into first segments present in the ghosted file, second segments pending to be reconstituted from an alternate location to the ghosted file, and third segments that are not first or second segments. Reconstitution of any third segments is initiated to convert same to second, pending segments, and the read command is responded to with the requested range of the data once all second segments are in fact reconstituted from the alternate location to the ghosted file and thus converted to first, pending segments.

A computing device has a file stored on a storage volume by a file system and accessed through such file system. The file is defined to include data and metadata relating to the data, and at least a portion of the data of the file is removed from the file and stored at an alternate location such that the data does not occupy substantially any space on the volume and the file is in a reduced, ghosted form. The ghosted file is reconstituted for use by retrieving the data from the alternate location and associating such retrieved data with such ghosted file to form the reconstituted file.

A ghosting filter on a computing device perceives that a file is in a ghosted form and commands a file system of the device to retrieve ghosting information from the ghosted file. The ghosting filter receives a read command from an application on the device with respect to a portion of the data of the ghosted file. The read command has parameters including an offset into the portion of the data and a read length with respect to such portion. The ghosting filter initiates reconstituting of the portion of the data of the ghosted file based on the received ghosting information and data of the ghosted file at an alternate location, and after the portion of the data of the ghosted file has been reconstituted responds to the read command with the portion of the data requested.

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Newcastle, WA, United States of America

Christophe Franck Robert