Storage system snapshot assisted by SSD technology
First Claim
1. A system for taking a snapshot of a storage device comprising:
- a storage device comprising a first mapping table, the first mapping table including mapping information corresponding to data prior to a write action by the storage device, and a second mapping table, the second mapping table including mapping information corresponding to data after a write action by the storage device;
wherein the storage device is capable of a point in time copy of the storage device using the mapping information held by the first and second mapping tables.
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Accused Products
Abstract
A method and apparatus for taking a snapshot of a storage system employing a solid state disk (SSD). A plurality of mapping tables in the SSD store data needed to create a one or more point in time snapshots and a current view of the SSD. In response to a write command, the SSD executes its normal write process and updates its mapping tables to indicate the current view of the SSD and additionally retains the original data in a table of pointers to the original data, as the snapshot of an earlier state of the SSD. In the preferred embodiment, the innate ability of SSDs to write data to a new location is used to perform a point-in-time copy with little or no loss in performance in performing the snapshot.
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Citations
19 Claims
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1. A system for taking a snapshot of a storage device comprising:
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a storage device comprising a first mapping table, the first mapping table including mapping information corresponding to data prior to a write action by the storage device, and a second mapping table, the second mapping table including mapping information corresponding to data after a write action by the storage device; wherein the storage device is capable of a point in time copy of the storage device using the mapping information held by the first and second mapping tables. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for a Solid State Disk snapshot comprising the steps of:
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storing data on a solid date disk (SSD); providing a first mapping table for address translation for the SSD; providing a second mapping table for address translation for the SSD; wherein said SSD is capable of a point in time copy of the SSD using the mapping information held in the first and second mapping tables; storing in the first mapping table data relating to the snapshot of the SSD;
storing in the second mapping table data relating to the current view of the SSD; andconstructing the snapshot of the SSD using the data in the first and second mapping tables. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. A system for taking a point-in-time copy of a SSD storage system comprising:
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means for storing data comprising a SSD; said SSD storage means having means for address translation comprising a first lookup table, said first lookup table holding data relating to a point-in-time copy of the SSD; said SSD storage means having means for address translation comprising a second lookup table, said second lookup table holding data relating to the current view of the SSD; means for writing data, said data writing means comprising means for executing a redirect-on-write; wherein, said SSD uses the first and second lookup tables to construct a snapshot of the SSD; means for setting data indicia to indicate whether to take a snapshot; means for updating said first and second lookup tables, with data pointers, in response to said data indicia setting means indicating to take a snapshot; a plurality of first and second lookup tables on a plurality of SSDs to enable the taking of multiple snapshots; means for enabling on at least one of said plurality of SSDs the taking of a system level data snapshot on data sets stored in said SSDs; and
,means for terminating snapshot data in response to a command to terminate a snapshot.
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Specification