Tracking in-progress writes through use of multi-column bitmaps
First Claim
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1. A method comprising:
- creating a data volume;
creating a copy of the data volume;
a computer system receiving a request to write first data to the data volume;
switching the state of a pair of bits in a memory device in response to the computer system receiving the request to write first data to the data volume, wherein the state of the pair of bits are switched using a single write access to the memory device.
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Abstract
Disclosed is a method and apparatus for tracking in-progress writes to a data volume and a copy thereof using a multi-column bit map. The method can be implemented in a computer system and, in one embodiment, includes creating a data volume in a first memory, and creating a copy of the data volume in a second memory. In response to the computer system receiving a request to write first data to the data volume, the computer system switches the state of first and second bits of a map entry in a memory device, wherein the state of the first and second bits are switched using a single write access to the memory device.
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Citations
11 Claims
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1. A method comprising:
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creating a data volume; creating a copy of the data volume; a computer system receiving a request to write first data to the data volume; switching the state of a pair of bits in a memory device in response to the computer system receiving the request to write first data to the data volume, wherein the state of the pair of bits are switched using a single write access to the memory device. - View Dependent Claims (2, 3, 4)
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5. A computer readable medium comprising instructions executable by a computer system, wherein the computer system performs a method in response to executing the instructions, the method comprising:
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creating a data volume; creating a copy of the data volume; switching the state of a pair of bits in a memory device in response to the computer system receiving a request to modify first data of the data volume, wherein the state of the pair of bits are switched using a single write access to the memory device. - View Dependent Claims (6, 7, 8, 9)
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10. A computer readable medium comprising instructions executable by a computer system, wherein the computer system performs a method in response to executing the instructions, the method comprising:
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creating a data volume; creating a mirror of the data volume; creating a map in a memory device, wherein the map comprises a plurality of entries, wherein each entry comprises first and second bits; wherein each first bit, when set to a first or second state, indicates whether data has been written to a respective block of the data volume since allocation of memory for the map; wherein each second bit, when set to a first or second state, indicates whether respective blocks in the data volume and mirror will be subject to separate in-progress write operations. - View Dependent Claims (11)
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Specification