System and method for reconstructing lost data in a storage system
First Claim
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1. A method for partial strip reconstruction in a storage system in which a plurality of lost strips have been detected, said method comprising:
- using a combination of a direct reconstruction method and a sequential reconstruction method to reconstruct said partial strip, as executed by a processor of a computer,wherein said sequential reconstruction method reconstructs a data element, from an input set of data elements to reconstruct, by collapsing said sequential reconstruction method to reduce cost,wherein said collapsing said sequential reconstruction method comprises at least one of;
using implicit intermediate results to reconstruct said data element;
determining whether any unnecessary data elements exist in at least one strip of the plurality of lost strips that are not part of said partial strip, and combining at least a portion of steps in said sequential reconstruction method to eliminate reconstruction of said unnecessary data elements;
avoiding unnecessary use of data elements that are not lost;
avoiding duplicate use of data elements that are not lost; and
avoiding multiple use of data elements that are not lost.
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Abstract
A system (and method) for determining reconstruction formulas for partial strip reconstruction in a storage system in which a plurality of lost strips have been detected, includes using a combination of a direct reconstruction method and a sequential reconstruction method.
27 Citations
15 Claims
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1. A method for partial strip reconstruction in a storage system in which a plurality of lost strips have been detected, said method comprising:
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using a combination of a direct reconstruction method and a sequential reconstruction method to reconstruct said partial strip, as executed by a processor of a computer, wherein said sequential reconstruction method reconstructs a data element, from an input set of data elements to reconstruct, by collapsing said sequential reconstruction method to reduce cost, wherein said collapsing said sequential reconstruction method comprises at least one of; using implicit intermediate results to reconstruct said data element; determining whether any unnecessary data elements exist in at least one strip of the plurality of lost strips that are not part of said partial strip, and combining at least a portion of steps in said sequential reconstruction method to eliminate reconstruction of said unnecessary data elements; avoiding unnecessary use of data elements that are not lost; avoiding duplicate use of data elements that are not lost; and avoiding multiple use of data elements that are not lost. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A system for partial strip reconstruction in a storage system, said system comprising:
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a storage unit of said storage system including an input set of data elements to reconstruct; and means for reconstructing a data element from said input set of data elements to reconstruct based on a combination of a direct reconstruction method and a sequential reconstruction method, wherein said means for reconstructing reconstructs a data element, from an input set of data elements to reconstruct, by collapsing said sequential reconstruction method to reduce cost, and wherein said means for reconstructing collapses said sequential reconstruction method by at least one of; using implicit intermediate results to reconstruct said data element; determining whether any unnecessary data elements exist in at least one strip of the plurality of lost strips that are not part of said partial strip, and combining at least a portion of steps in said sequential reconstruction method to eliminate reconstruction of said unnecessary data elements; avoiding unnecessary use of data elements that are not lost; avoiding duplicate use of data elements that are not lost; and avoiding multiple use of data elements that are not lost. - View Dependent Claims (12, 13, 14)
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15. A tangible signal-bearing storage medium tangibly embodying a program of machine-readable instructions executable by a digital processing apparatus to perform a method for determining reconstruction formulas for partial strip reconstruction in a storage system, using, selectively, a combination of a direct reconstruction method and a sequential reconstruction method, said method comprising:
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determining, using a processor on a computer, a reconstruction cost for executing said reconstruction, respectively, using said direct reconstruction method, using said sequential reconstruction method, and using a combination of said direct reconstruction method and said sequential reconstruction method; and using a reconstruction formula for said partial strip reconstruction for whichever said reconstruction method is determined to have a lowest reconstruction cost, wherein said sequential reconstruction method reconstructs a data element, from an input set of data elements to reconstruct, by collapsing said sequential reconstruction method to reduce cost, wherein said collapsing said sequential reconstruction method comprises at least one of; using implicit intermediate results to reconstruct said data element; determining whether any unnecessary data elements exist in at least one strip of the plurality of lost strips that are not part of said partial strip, and combining at least a portion of steps in said sequential reconstruction method to eliminate reconstruction of said unnecessary data elements; avoiding unnecessary use of data elements that are not lost; avoiding duplicate use of data elements that are not lost; and avoiding multiple use of data elements that are not lost.
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Specification