Computer system
AssigneeKabushiki Kaisha Toshiba
InventorKazunori Sekido
Life of this patent
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Abstract
Snapshot management means intervenes between a file system for managing access, including update, to files stored in nonvolatile storage devices and the nonvolatile storage devices. The snapshot management means creates a snapshot holding the contents of the files at a specific point in time for each of the nonvolatile storage devices and stores the created snapshot into the corresponding nonvolatile storage device. The configuration makes it possible to create snapshots effectively without any modification to application programs or a file system.
Claims30
A computer system provided with a file system for managing access to files stored in a nonvolatile storage device, comprising:
- snapshot management means which intervenes between said file system and said nonvolatile storage device, and which creates accumulated blocks of write-in data supplied from said file system, to be supplied to nonvolatile storage device in log form, and stores said accumulated blocks of said write-in data and logical address tag information created based on a logical address and time stamp of said write-in data, in said nonvolatile storage device as a snapshot.
A data sheltering method in a computer system provided with a file system for managing access to files stored in a nonvolatile storage device and writing buffer with a storage capacity equivalent to a K number of logical blocks, comprising:
- the step of accumulating logical blocks of data items to be updated in said writing buffer in a normal writing process;
- the step of delaying the update of the data items in the logical blocks until the number of the accumulated logical blocks has reached K−1;
- the step of creating a logical address tag block composed of the logical addresses for the individual logical blocks accumulated in said writing buffer;
- the step of adding a time stamp for maintaining the temporal order of writing to the logical address block;
- the step of adding said logical address tag block to a K−1 number of blocks to form one stripe containing a K number of logical blocks and writing stripes consecutively in an empty area different from the area holding the data to be updated on said nonvolatile storage device;
- the step of determining the logical addresses for a K−1−L number of logical blocks in said writing buffer unfilled with the logical blocks of data items to be updated at the time of creating a snapshot to be null addresses in a snapshot creation process of creating a snapshot holding the contents of said file at a specific point in time;
- the step of creating a logical address tag block composed of the logical addresses for an L number of logical blocks accumulated in said writing buffer at the time of creating the snapshot and said null addresses;
- the step of adding a time stamp for maintaining the temporal order of writing to the logical address tag block;
- the step of adding said logical address tag block to a K−1 number of blocks including said L number of logical blocks to form one stripe containing a K number of logical blocks and writing stripes consecutively in an empty area different from the area holding the data to be updated into said nonvolatile storage device;
- and
- the step of recording said added time stamp as snapshot information.
Dependencies are inferred from the claim text.