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US 6,957,362 B2Granted
Instantaneous restoration of a production copy from a snapshot copy in a data storage system
AssigneeEMC Corporation
InventorPhilippe Armangau
Life of this patent
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AssigneeEMC Corporation
InventorPhilippe Armangau
Estimating the term…
A data storage system maintains a production dataset supported by a clone volume, and multiple snapshot datasets supported by respective save volumes in a snapshot queue. In order to instantaneously restore the production dataset with the state of any specified snapshot, the data storage system responds to requests for read/write access to the production dataset by reading from the specified snapshot dataset and writing to the production dataset. The data storage system keeps a record of data blocks that have been modified by writing to the production dataset. The data storage system initiates a process of copying data blocks from the specified snapshot dataset to the production dataset if the record of the data blocks indicates that the data blocks have not yet been modified by writing to the production dataset.
A data storage system for providing access to a production dataset and at least one snapshot dataset, the data storage system comprising storage containing the production dataset and the snapshot dataset, the snapshot dataset being the state of the production dataset at a point in time when the snapshot dataset was created,
A data storage system for providing access to a production dataset and at least one snapshot dataset, the data storage system comprising storage containing the production dataset and the snapshot dataset, the snapshot dataset being the state of the production dataset at a point in time when the snapshot dataset was created, the data storage system being programmed for instantaneous restoration of the production dataset with the state of the snapshot dataset by responding to requests for read/write access to the production dataset by reading from the snapshot dataset and writing to the production dataset, and keeping a record of data blocks that have been modified by said writing to the production dataset, and initiating a process of copying data blocks from the snapshot dataset to the production dataset if said record of the data blocks indicates that the data blocks have not yet been modified by said writing to the production dataset.
A file server for providing access to a production file system and a plurality of snapshot file systems, each of the snapshot file systems being the state of the production file system at a respective point in time when said each of the snapshot file systems was created,
A method of operating a data storage system providing access to a production dataset and at least one snapshot dataset, the data storage system including storage containing the production dataset and the snapshot dataset, the snapshot dataset being the state of the production dataset at a point in time when the snapshot dataset was created, wherein the method comprises instantaneous restoration of the production dataset with the state of the snapshot dataset by initiating read/write access through a foreground routine to what appears to be a restored version of the production dataset while the production dataset is being restored by a background routine, the foreground routine keeping a record of data blocks that have been modified by the read/write access through the foreground routine since initiating the read/write access through the foreground routine, the background routine copying data blocks from the snapshot dataset to the production dataset if said record of the data blocks indicates that the data blocks have not yet been modified by the read/write access through the foreground routine since initiating the read/write access through the foreground routine.
A method of operating a data storage system for providing access to a production dataset and at least one snapshot dataset, the data storage system including storage containing the production dataset and the snapshot dataset, the snapshot dataset being the state of the production dataset at a point in time when the snapshot dataset was created, said method comprising instantaneous restoration of the production dataset with the state of the snapshot dataset by responding to requests for read/write access to the production dataset by reading from the snapshot dataset and writing to the production dataset, and keeping a record of data blocks that have been modified by said writing to the production dataset, and initiating a process of copying data blocks from the snapshot dataset to the production dataset if said record of the data blocks indicates that the data blocks have not yet been modified by said writing to the production dataset.
A method of operating a file server for providing access to a production file system and a plurality of snapshot file systems, each of the snapshot file systems being the state of the production file system at a respective point in time when said each of the snapshot file systems was created, the file server including storage containing a clone volume of data blocks supporting the production file system, and the storage containing, for said each of the snapshot file systems, a respective save volume of data blocks supporting said each of the snapshot file systems, the respective save volume of said each of the snapshot file systems containing data blocks having resided in the clone volume at the respective point in time when said each of the snapshot file systems was created, wherein said method comprises:
Dependencies are inferred from the claim text.