Reading data provided to a remote storage device
First Claim
1. A method of reading desired data from a remote storage device that receives chunks of data from an other storage device, comprising:
- determining if the desired data is part of a chunk of data committed by the other storage device;
if the desired data is not part of a chunk of data committed by the other storage device, reading the desired data from a corresponding standard logical device; and
if the desired data is part of a chunk of data committed by the other storage device, transferring the desired data to the standard logical device and obtaining the desired data from one of;
the standard logical device after transferring the desired data thereto and the chunk of data committed by the other storage device.
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Accused Products
Abstract
Reading desired data from a remote storage device that receives chunks of data from an other storage device includes determining if the desired data is part of a chunk of data committed by the other storage device, if the desired data is not part of a chunk of data committed by the other storage device, reading the desired data from a corresponding standard logical device, and if the desired data is part of a chunk of data committed by the other storage device, transferring the desired data to the standard logical device and obtaining the desired data from one of: the standard logical device after transferring the desired data thereto and the chunk of data committed by the other storage device. Reading desired data from a remote storage device may also include, if the desired data is part of a chunk of data committed by the other storage device, locking a corresponding slot of a cache only virtual device that points to the desired data. Reading desired data from a remote storage device may also include, locking a corresponding slot of the standard logical device, merging corresponding cache slots, and causing the corresponding slot of the cache only virtual device to point to the standard logical device.
74 Citations
20 Claims
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1. A method of reading desired data from a remote storage device that receives chunks of data from an other storage device, comprising:
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determining if the desired data is part of a chunk of data committed by the other storage device; if the desired data is not part of a chunk of data committed by the other storage device, reading the desired data from a corresponding standard logical device; and if the desired data is part of a chunk of data committed by the other storage device, transferring the desired data to the standard logical device and obtaining the desired data from one of;
the standard logical device after transferring the desired data thereto and the chunk of data committed by the other storage device. - View Dependent Claims (2, 3, 4, 5)
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6. A method for a host coupled to a remote storage device to read desired data transmitted by a local storage device, comprising:
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identifying a most recent and consistent set of data containing the desired data; and obtaining the desired data from the most recent and consistent set of data, wherein the set of data is a chunk of data committed by the local storage device and wherein the chunk of data is assigned a sequence number that is less than a sequence number for other chunks of data containing other data that an other host computer started to write after starting to write the desired data. - View Dependent Claims (7, 8)
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9. Computer software that reads desired data from a remote storage device that receives chunks of data from an other storage device, the software comprising:
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executable code, in a computer readable medium, that determines if the desired data is part of a chunk of data committed by the other storage device; executable code, in a computer readable medium, that reads the desired data from a corresponding standard logical device if the desired data is not part of a chunk of data committed by the other storage device; and executable code, in a computer readable medium, that transfers the desired data to the standard logical device and obtains the desired data from one of;
the standard logical device after transferring the desired data thereto and the chunk of data committed by the other storage device if the desired data is part of a chunk of data committed by the other storage device. - View Dependent Claims (10, 11, 12, 13)
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14. Computer software for a host coupled to a remote storage device to read desired data transmitted by a local storage device, comprising:
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executable code, in a computer readable medium, that identifies a most recent and consistent set of data containing the desired data; and executable code, in a computer readable medium, that obtains the desired data from the most recent and consistent set of data, wherein the set of data is a chunk of data committed by the local storage device and wherein the chunk of data is assigned a sequence number that is less than a sequence number for other chunks of data containing other data that an other host computer started to write after starting to write the desired data. - View Dependent Claims (15, 16)
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17. A data storage device that provides a desired chunk of data from a plurality of chunks of data from an other storage device, comprising:
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a cache memory that receives the plurality of chunks of data provided to the data storage device from the other storage device; a plurality of disks that store chunks of data from the cache memory that have been committed by the other storage device; executable code, in a computer readable medium, that determines if the desired data is part of a chunk of data committed by the other storage device; executable code, in a computer readable medium, that reads the desired data from at least one of the disks if the desired data is not part of a chunk of data committed by the other storage device; and executable code, in a computer readable medium, that, if the desired data is part of a chunk of data committed by the other storage device, transfers the desired data to at least one of the disks and obtains the desired data from one of;
at least one of the disks after transferring the desired data thereto and the cache memory. - View Dependent Claims (18, 19, 20)
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Specification